CROP PRODUCTION AND HEALTH SCIENCES

CPH01 IRRIGATION PRACTICES IN THE MALTESE ISLANDS WITH PARTICULAR REFERENCE TO THE USE OF BRACKISH WATER WITH TRICKLE IRRIGATION
 

Irrigated land in Malta forms only about 11.7% of the total arable land and most of the irrigated land belongs to medium-sized farms (2.25 - 2.50 ha). Furrow irrigation is still the most popular method of irrigation but use of sprinklers and trickle irrigation is widespread. The Harbour Region and the Northern Region are richest in irrigated land; however, the high density occurs in the Western Region.
Four main sources  of irrigation waters could be identified - perched aquifer, sea level upper water table , mean sea level lower level water table and treated effluent. When these are assessed for salinity levels, it was found that the perched aquifer has the lowest electrical conductivity while the sea level upper water table ha the highest level. The treated effluent and the sea level upper water table have similar mean electrical conductivity levels to the mean sea level lower water table, but are different from each other. Salinity in aquifers with hydraulic contact with sea water is mainly attributed to overpumping and subsequent salt water intrusion.
Armier waters have the highest mean electrical conductivity level and is classified as having very high salinity according to the USDA classification. Burmarrad, Pwales and the South-East Region follow closely with high salinity while Mellieha, Qormi, Rabat and Mgarr mean electrical conductivity levels are considered to be of medium salinity. Siggiewi is the only locality with waters of moderate salinity according to the USDA classification.
Research  Worker: Joanne Muscat
Project Supervisor: Prof. Anthony Scicluna-Spiteri
 

CPH02 MICROPROPAGATION OF SOLANUM TUBEROSUM VARIETIES FOR THE PRODUCTION OF SEED TUBERS
 

Micropropagation of two potato varieties (Alpha and Desiree) was carried out for the production of seed tubers. In vitro virus-free cultures of Desiree and Alpha were obtained from the plant tissue collection of the Institute of Biological Research, Belgrade. A culture for another genotype of the Alpha variety (Alpha M) was started from tubers harvested from Maltese soils. The breaking of dormancy in tubers to produce sprouts which were used as explants for starting cultures was carried out by treating the tubers with gibberellic acid (GA3). Several methods of surface sterilization of these explants were carried out, and the best results were achieved by using disinfectant (1%), antibiotic (2%) and bleach (2% sodium hypochlorite) solutions. The effect of two plant growth regulators (Benzylaminopurine [BAP] and GA3) was studied, and it was confirmed that BAP (a cytokinin) induced shoot growth but does not promote root development. This effect was enhanced when GA3 was added to the nutrient medium.
Micro-tubers were produced from plantlets grown on multiplication medium, then transferred in tuberization medium and placed in very low light conditions. Tuberization medium contained high levels of BAP (5 mg/ml) and sucrose (8 %). The production of microtubers was studied for plantlets growing on two types of media (liquid and semi-solid), and the best type was found to be semi-solid. The variety with the highest yield was found to be the Alpha variety. The effect of multiplication medium which contained encymidol as a growth retardant was also studied, and it was found that this type of medium enhanced axillary shoot development. This effect was however greater for the Desiree variety.
Mini-tubers were produced from micropropagated plantlets which were transferred into soil. The production of mini-tubers was studied for the Desiree variety growing on two types of potting mixtures (compost and peat). It was found that plants in compost produced more mini-tubers which were also larger. The production of mini-tubers from Alpha and Alpha M was also investigated and compared, and it was found that Alpha M produced more mini-tubers, but these were however smaller than those produced by Alpha.
Research  Worker: Noel Azzopardi
Project Supervisor: Prof. Radmila Vujicic
 

CPH03 THE NUTRITIVE VALUE OF FORAGE CROPS IN THE MALTESE ISLANDS
 

The cultivation of forage crops in the Maltese Islands is an important agricultural industry which provides an essential feed input to the livestock sector. The contribution of these crops as fodder for animal feeding may be illustrated by quantifying the nutritional value of the forage crops and the ability of the local fodder production to meet the demand generated.
Based on current census information, the estimated available supply of fodder is sufficient to meet only approximately 38% of the total amount of roughage required for animal feeding.
In this study, chemical composition data was compiled of the three major forage crops cultivated in the Maltese Islands - wheat, barley and sulla - at five different stages during their development. The results indicated sulla as a more highly nutritious forage crop, in comparison to wheat and barley, since it was characterised by higher cell contents and soluble cell components, and lower cell walls fractions at levels corresponding to the recommended dairy cattle feed requirements.
The development of the forage crops was characterised by a general increase in the total crop yield, parallelled by a deterioration in quality as maturation progressed, defined by an increase in the structural components and a decrease in digestible and available fractions.
The optimum harvesting stages for the forage crops under study were identified on a calendar basis, using the dry matter digestibility criterion.
In this respect, Fiddien sulla (a foreign variety) was highlighted as an ideal crop since it can be harvested at a stage when both dry matter digestibility and dry matter protein yields are at a maximum.
Research  Worker: Sonya Vella
Project Supervisor: Prof. Anthony Scicluna-Spiteri
 

CPH04 PESTICIDE SALES AND THE ROLE OF THE PHARMACIST

Three different questionnaires, each addressing a different group of people, were drawn up and distributed to community pharmacists, pesticide importers and/or retailers and the Agricultural Extension Service personnel of the Department of Agriculture with the main purpose of understanding what those interviewed think of the current situation of pesticide use and/or misuse in Malta
and secondly, to promote the idea that to sell pesticides, a person should be suitably qualified. Few pharmacies stock household pesticides while none sell agricultural pesticides as these are being sold mainly in agricultural co-operatives' retail outlets. However it is felt that the sale of pesticides should be restricted to specialised shops run by qualified personnel as pesticides are toxic chemicals. Importers recognise this need but do not consider pharmacists to be candidates for this job. But if given specialised training, pharmacists would certainly be qualified, especially as they are aware of pesticide toxicity as they sometimes meet cases of such poisoning. The general public is not believed by the respondents to be conscious enough of how harmful pesticides can be.
Farmers themselves do not usually wear protective clothing or other equipment.
The private sector imports much more pesticides than the government does mostly fungicides and insecticides while herbicides seem to be rarely utilised. Locally packed pesticide preparations are labelled in Maltese and English, but foreign preparations sometimes have no label or are labelled in some unfamiliar language. A more judicious use of pesticides is gradually being introduced by agricultural officers who are promoting integrated pest management during meetings which are held far farmers. A bill has been recently passed far the first reading in Parliament aiming to update the legislation. Practising as a health educator in the agricultural sphere of society would project a better professional image, a more satisfying role for any pharmacist and would represent a way forward for pharmacy.
Research  Worker: Victor Pace
Project Supervisor: Dr. Antoine Vella

CPH05 THE UTILISATION OF OPUNTIA FICUS-INDICA
 

Opuntia ficus indica was introduced in Spain at the end of the 15th century and from there spread over the whole Mediterranean basin. In Malta the plant has been used extensively in the past as a source of fodder for ruminants. However the plant was never studied scientifically. Therefore the two objectives of the study were to determine the nutritional value of the plant and to evaluate the current and potential uses of the plant for the benefit of Maltese farmers.
In the first study the proximate analysis technique was used to determine the nutritional value of the plant. In the second study a survey was carried out to determine the current uses of the plant by Maltese farmers. It's potential uses were examined by means of extensive literature review.
From the study it was established that the gross composition of Opuntia ficus indica as determined by standard procedures on dry weight basis were : crude protein content of 11.03%, a crude fibre content of 8.94%, a nitrogen free extract of 54%. , an ash content of 23.53% , a lipid content of 2.48 %  and a moisture content of 90.75%. Its calculated metabolising energy value was of 8.46Mj /kg of dry matter.
From the second study it was established that all sixteen farmers interviewed feed Opuntia ficus indica pads to their ruminants from May to early November as a supplementary feed. Preparation of Opuntia ficus indica as fodder involves cutting the pads early in the morning, chopping the pads into small pieces and feeding the pads directly to the animal. It was established that ruminants eat the pads eagerly. None of the farmers ever encountered feeding accidents from spines present and besides feeding of Opuntia ficus indica in no way effect the colour or taste of milk.
Several reasons were given by farmers  why they feed their animals Opuntia ficus indica. Some said because it was easily available and cheap, therefore a good cost cutting measure (55%), others due to its  high nutritional value (35 %), while some claimed that it increases milk production and allows the animal to give birth more easily (10 %).
It was established that 90% of the farmers planted the plant as a wind breaker and protective hedge in the first place rather than as a source fodder for animals. Only the remaining 10% of the farmers planted Opuntia ficus indica  primarily as a source of fodder.
Based on the above results it was concluded that  the plant is extensively used as a protective hedge and to a lesser extent as a source of fodder. Ruminants find no problem in consuming Opuntia ficus indica and no negative effects were observed . The plant was found to be rich in carbohydrates, lipids and moisture. However contrary to what was expected, the crude protein content of the plant was found to be very similar to that of grasses, while its crude fibre content was found to be quite low. When the plant is used as a supplement, it has a number of advantages.
It has been estimated that feeding a flock of sixteen sheep 60 kg of fresh pads daily saves the farmer two bales of hay . This would  amount to saving £2.50 per day during (the period May to November). Moreover various  studies suggest that due to the high palatability of the plant the consumption of low quality forage would be increased. Some authors actually suggest that the plant increases milk production. The exact mechanism is not known however it has been postulated that the plant may actually increase cellulolytic activity in the rumen.
Throughout this study it was observed that Opuntia ficus indica has been consumed by humans and ruminants alike for more than four centuries without any deleterious effect. Thus it was concluded that under the circumstances herein described no harm would be expected to ruminants consuming the plant.
Research  Worker: Stephen Cilia
Project Supervisor: Prof. Anthony Scicluna-Spiteri

CPH06 AN INVESTIGATION ON THE CONTROL OF THE MEDITERRANEAN FRUIT FLY (CERATITIS CAPITATA [WIEDEMANN]) ON CITRUS, THROUGH MASS TRAPPING
 

The Mediterranean fruit fly, Ceratitis capitata [Wiedemann], is a very destructive pest which attacks over 250 fruits, nuts and vegetables but predominantly citrus fruit such as orange.  In certain countries, citrus losses have run as high as 50%.
In 1888 on being asked how to deal with Ceratitis capitata, referred in Malta as the orange fly, Professor Cannestrini answered that it would get rid of itself in not more than four years.  We are now a hundred and ten years from that date and the damage caused by the Mediterranean fruit fly does not seem to have diminished yet. The agricultural industry is continuously striving to find cheap, efficient and safe ways how to control the pest.  This study aims to investigate mass trapping with specific baits as a means of controlling Ceratitis capitata.  Two different baits, trimedlure and sucrose solution were tested.  The insects caught with these traps were analysed and the means of the Ceratitis capitata caught by the two different baits were utilised to find out if there is any statistically significant difference between the two respective means.
Trimedlure, a gender-specific bait, was found to be much more effective in controlling Ceratitis capitata than the sucrose solution!
Research  Worker: Mark L. Zammit
Project Supervisor: Dr. Antoine Vella
 

CPH07 THE USE OF CITRIC ACID SPRAYS TO CONTROL IRON DEFICIENCY CHLOROSIS ON LOCAL FRUIT TREES
 

Fruit trees growing on highly calcareous soils are prone to suffer from lime induced iron deficiency.   The high bicarbonate content causes an inactivation of the iron present in the leaves so that it could not be utilized in the generation of chlorophyll.
It is a well known and proven fact that many a time chlorotic leaves contain more iron than healthy green ones.   This has led researchers over the years to try to unravel the mechanisms involved in unlocking the present iron from the inactive to the active state.   It was hypothesised that the enzyme Fe3 reductase located in the plasmalemma which is responsible for the temporary conversion of iron is pH dependent.   This hypothesis was proved right since after spraying solutions known to lower the pH, regreening occurred.
In this study a small pear orchard growing on clay soil which had shown in previous years severe signs of iron chlorosis was challenged using a concentration of 6000mg L-1 of citric acid spray.   The field was split up into six main blocks consisting of six trees each, half of which were sprayed while the others were left as controls.   Spraying was carried out on a weekly basis.   At the end of a three month period, leaf specimens from each tree were taken to the laboratory for further analysis.   Chlorophyll extraction was carried out using acetone and the extracts were then submitted to spectrophotometer readings.   Chlorophyll concentration is said to reflect the iron nutritional status of the plant.
Leaf regreening clearly indicated the reactivation of iron in sprayed leaves, however, statistical analysis did not prove any significance between sprayed and unsprayed trees.
A survey was carried out and the replies resulted in a highly statistical significance between trees growing on raw carbonate soil and the incidence of iron chlorosis.   Furthermore a significant P value resulted from analysis between the addition of farmyard manure and the incidence of iron chlorosis.   The agricultural chemist has a vital role to play in ensuring the prevention rather than the cure of iron chlorosis.  Analysis and upgrading of the soil, the planting of resistant cultivars, the addition of farmyard manure or compost and the use of foliage spray all prove to be useful tools in the hands of research workers in their constant struggle against the problem of iron chlorosis.
Research  Worker: Ivan Costa
Project Supervisor: Prof. Anthony Scicluna-Spiteri
 

CPH08 A SURVEY OF THE INCIDENCE OF POTATO CYST NEMATODES (GLOBODERA SPP.) IN MALTA

The potato cyst nematodes Globodera rostochiensis and Globodera pallida are among the most important pests of the potato crop in Europe. With export of this crop reaching, 4,463 tons for the period of April to May this year, it is evident how important this crop is for our local economy.
The aims of this project were

1. to determine the incidence of potato cyst nematode infections in the Maltese Islands and

2. to try to identify, as much as possible whether both Globodera rostochiensis and Globodera pallida are present on the island.

For this purpose, 30 potato growing fields from around the island were analysed. An incidence of 23 % was encountered since 7 samples out of the 30 analysed were found to contain the Globodera cysts. The infestations encountered were rather low except for 3 fields namely at Mgarr, Kirkop and Rabat where high infestation rates were encountered.
An indirect ELISA technique was used for the first time for identification of potato cyst nematodes. From the 5 samples analysed Globodera pallida was not detected. This seems to suggest that this potato cyst nematode is absent from the island.
Research  Worker: David Baldacchino
Project Supervisors: Dr. Antoine Vella & Ms. Inga Zasada
 

CPH09 RESIDUES OF CYPERMETHRIN, DIMETHOATE AND METALAXYL IN LOCALLY HARVESTED CARROTS

Importation of pesticides in Malta during 1997 was of over 220,000 kg and over 20,000L, indicating the high use of pesticides on crops that are grown locally and most of which are also consumed locally.
The study had principally two aims. One of them was the participation in an interlaboratory study within the European Union in order to validate and extraction method. This study was organized by the European Commission while Central Science Laboratory in England acted as the coordinating laboratory. Excluding Malta 25 laboratories participated in this study. Although Malta is not a member of the European Union, the coordinating laboratory still gave us this opportunity to participate in this study. For this part of the study 6 pesticides were studied : chlorfenvinphos, cypermethrin, dimethoate, omethoate, metalaxyl and triazophos.
The presence or absence of 3 of these pesticides in locally harvested carrots was then studied. These 3 pesticides were: cypermethrin, dimethoate and metalaxyl. This since in Malta importation of chlorfenvinphos is banned, while that of omethoate and triazophos is restricted. This however does not exclude the possibility that such pesticides could be present in locally produced carrots. In fact this same study could be continued and testing for these other three pesticides will be carried out.
The results obtained in testing for pesticide residues can be influenced by a number of factors including: training of scientific and technical personnel, working state of the equipment used which is of high technology, and degree of purity of solvents and reagents. For the study, certified pesticide standards were used and all other reagents and solvents were purchased from reliable suppliers ensuring on labels that such products could be used for analysis involving the use of equipment of high technology.
The instrumentation employed in this study for both the validation of the extraction method and the final determination of presence or absence of pesticide residues in locally produced carrots was the gas chromatograph with an electron capture detector. It should be noted here that the carrot samples were collected from various supermarkets and vegetable hawkers all over Malta and Gozo.
Gozo -  Marsalforn, Victoria, Xlendi, Sannat and Xewkija.
Malta - Mellieha, Burmarrad, Mosta, Birkirkara, Rabat, Qormi, Msida, Valletta, Zabbar, Marsaxlokk, Birzebbugia.
Pesticide residue analysis is not an easy task involving a number of steps before eventually concentration of pesticide in a crop is found. Such steps include:

1. preparation of stock solutions;

2. preparation of working stock solutions;

3. preparation of standard solutions;

4. preparation of spiked solutions;

5. injecting of standard solutions in gas chromatograph so that peak area for each pesticide is determined and thus calibration curves for each one could be prepared;

6. injecting once again with the spiked solutions. Such solutions would have present a representative sample of the homogenized crop besides that particular pesticide whose concentration is being assessed;

7. from peak areas, that are given automatically by the gas chromatograph for the spiked solutions, calibration curves are prepared;

8. comparison of calibration curves for standard and spiked solutions for percentage recovery.

9. From the results obtained it can be concluded that percentage recovery of the pesticides was not 100% as was expected. This could have been due to various experimental errors including:

10. losses while performing the injections which were performed manually;

11. although same solution was injected more than once, no replications were done;

12. there was not enough time to repeat the whole experiment;

13. the extraction method is still in its validation stage in the European Union;

14. studies of recovery are also still in their validation stage in the European Union.

Regarding the second aim, none of the 3 pesticides studied were found to be present in the locally harvested carrot samples.
Keeping in mind the quantities of pesticides imported locally; the ambitions of our local farmers to export locally grown crops to countries within the European Union; and the tourist industry; studies similar to this one should be further encouraged. Such studies will not only help farmers in regulating amounts of pesticides used, but would also ensure a better life quality to all concerned.
Research  Worker: Helen Debono
Project Supervisor: Dr. Antoine Vella
 

CPH10 STUDY ON THE QUALITY OF IRRIGATION WATERS
 

The lack of information on the water quality of irrigation waters in the local agricultural industry calls for a dire need to study various parameters of irrigation water. This project was intended to carry out a survey along the Maltese islands to study water quality trends in the Maltese water table. The variations in water quality will be considered not only on topographical and geomorphologic characteristics but also due to the effects of industry, drainage water and livestock in respect to growth of crops and public health. The study will also serve as reference data as to irrigation water quality. Moreover the effects of the parameters studied on the agricultural industry will be discussed in view of the European Union guidelines and limits particularly by studying the possible and major causes of nitrate pollution in groundwater either due to intensive use of fertiliser or from intensive animal husbandry.
The survey will be carried out on a representative sample approximately sixty taken from on site sources and considered as agriculturally intense regions will be tested for the following parameters namely:
a. Electrical Conductivity- by conductivity meter in terms of total dissolved solids. This was then related with salinity.
b. Chlorides- by titrimetry in terms of water salinity and classified accordingly according to USDA classification of irrigation waters.
c. Sodium- by or atomic absorption spectrophotometry in terms of groundwater sodicity. Again the data obtained was classified according to sodicity levels.
d. Nitrates- by steam distillation as total nitrogen. The levels were then treated with relation to location near farms or polluting sources and on type of irrigation water.
e. pH- by a digital pH meter. The pH was studied in relation to nitrate content in waters
f. Total hardness - by titrimetry in terms of calcium hardness and magnesium hardness.
The samples will be taken from boreholes, surface run off and man made reservoirs. Additionally the samples will be adequately labeled as to site location, point of sampling source, and date when sampled. The tests will be carried out at the public health laboratory at Evans Building Valletta.
Research  Worker: David Farrugia
Project Supervisor: Prof. A. Scicluna-Spiteri
 

CPH11 ORGANIC AGRICULTURE IN MALTA

This research project is about organic crops presently grown in Malta by a few dedicated growers.
The aim of the dissertation is to evaluate the systems that are currently used by Maltese organic growers and to concentrate on the principles and preset practices of organic agriculture ( and the possibility of applying them to the Maltese situation). Finally it provides suggestions for the benefit of people who are actively involved with the agricultural industry.
Technical material was left out and the suggestions are inclined to be on the theoretical side. Direct personal contact is often far more convincing than any quantity of written material and the best way to know what organic agriculture is about and to look at the changes in management is to visit some of the organic fields. Three organic growers were visited and interviewed. In this dissertation the subject of biological control is given distinctive importance. Two growers who raise their crops in a greenhouses and utilize biological controls were visited.
The extensive use of organic manure obtained from livestock, compost and green manure seems to be synonymous  with organic agriculture, so a whole chapter was devoted to the subject of soil fertility.
It was found that conversion in Malta is still done in a haphazard manner.  It is associated with a severe lack of sound information and advice as well as the absence of appropriate research and development work. The knowledge of growers is usually more intuitive than scientific and this self-imposed limitation narrows the farmer ’s options.
Ready market does not exist and many growers believe that the only possible area for expansion would be to go offshore.
Research  Worker: Stephen Spiteri
Project Supervisor: Dr. Antoine Vella
 

CPH12 EFFECT   OF  POTASSIUM   FERTILISERS ON  CROPS   GROWN  ON  SALINE   SOILS

Two locally cultivated crops lettuce (Lactuca sativa) which is moderately salt sensitive and barley (Hordeum vulgare) which is moderately salt tolerant, were grown in pot experiments containing 3kg of local soil in order to investigate the effect of potassium fertilisation on yield improvement of plants subjected to salinity. After a preliminary study on a local lettuce variety, the experiment was repeated on a local barley variety and on the local lettuce variety. Two salinity levels 43mM and 80mM NaCl and two levels of potassium fertiliser were used, 1.25mM and 2.56mM K₂SO₄. In these experiments there were three replications for each of the nine nutritional treatments-Control, K₁S₀, K₂S₀, K₀S₁, K₀S₂, K₁S₁, K₂S₁, K₁S₂, K₂S₂. Treatment was initiated 14DAS for barley and 34DAS for lettuce. Plant heights were recorded weekly and finally the dry mass of the plants and grains or seeds produced were used as growth indices. Analysis revealed that for barley salinisation at both levels improved dry mass and plant height over that of the control and that fertilisation of both salinity treatments was beneficial only at the low potassium level, however this nutritional treatment failed to raise grain quality to control levels. Similar results were obtained from the experiments on the local lettuce variety. Salinisation of 43mMNaCl increased dry mass and final plant height and fertilisation of this salinity level with both potassium levels resulting in an additional increase in yield. Fertilisation of the 80mMNaCl treatments with both levels of K₂SO₄ caused further yield depression. Seed quality was adversely affected in all the salinity treatments .
In a third experiment commercially produced lettuce, var. Bionda Lenta was used. K₂SO₄ was replaced with KCl. One level of fertiliser 10mMKCl was used to fertilise two salinity treatments 40mM and 80mMNaCl. There were four replicates for each of the six treatments: Control, K₁S₀, K₀S₁, K₀S₂, K₁S₁, K₁S₂. Treatment was initiated 34DAS. Plant height and leaf surface area were measured weekly. Fresh mass and dry mass revealed that both levels of salinity depressed growth and KCl application further depressed yield. KCl fertilisation only improved the fresh yield of the low salinity treatments and the dry mass of the high salinity treatment. Soil composition was determined from a 1:2 soil: water extract both before and after the experiment. Leaf potassium and sodium concentrations determined by flame photometry revealed that potassium fertilisation improved potassium sodium ratio only in the low salinity treatment. At the low salinity level, KCl fertilisation resulted in increased sodium and potassium uptake. Depressed yield was attributed to environmental conditions especially high temperatures and to deterioration of the soil physical and chemical characteristics as a result of sodium chloride salinisation. After the experiment, the soil of the salinity treatments assumed the characteristics of saline sodic soils. Other methods of improving this experimental design, mainly an emphasis on saline soil reclamation are discussed.
Research  Worker: Melanie Grech
Project Supervisor: Prof. A. Scicluna-Spiteri
 

CPH13 AIR POLLUTION EFFECTS ON CROPS IN MALTA: A CASE STUDY ON SOLANUM TUBEROSUM

To date the issue of air pollution in Malta has not been addressed. The main aim of this research study was to evaluate the quality of the air in selected Maltese agricultural areas. Four sites were chosen in order to determine whether there exists any possible trend or relationship between the ambient air quality and the growth and yield of the potato (Solanum tuberosum).
The multiple interacting stress approach was adopted, whereby factors such as soil moisture deficit, soil fertility, meteorology and the co-occurrence of air pollutants were taken into account.
The results obtained from the air monitoring programme, which was conducted over two potato growing seasons, revealed that there is a spatial and temporal variation  in the levels and types of air pollution. Ozone exposure to the north of Malta commonly approached  or exceeded  the W.H.O. guideline and the E.U. threshold limits for crops. Most of the readings recorded for the nitrogen oxides exceeded the W.H.O. guideline values at all the sites. Sulphur dioxide concentrations were significantly higher to the southern and central regions of the island.
A negative correlation was obtained for root-to-shoot ratios and crop yields versus the ambient ozone concentrations. Synergism was also observed between ozone and sulphur dioxide. In contrast, a positive correlation was obtained for the root-to-shoot ratios and potato crop yields in relation to the nitrogen oxides. The results of the soil survey revealed that the levels of nitrate nitrogen in the soil were sub-optimal following the heavy rains in December and the potato plants may have used the nitrogen oxides as an alternative nitrogen source.
The negative effect of ground-level ozone on potato crop yields was very evident particularly during the second growing season. The higher levels found to the north of Malta could have a negative economical impact since agriculture is still extensively practiced and ozone sensitive species such as wheat, tomato, potatoes , onions, melons and vine trees are commonly cultivated in this region.
Data regarding the effects of ozone on crops in the Mediterranean is lacking and more research is needed to better characterize the adaptation mechanisms of Maltese plant receptors and to understand which environmental factors are modifying the response.
Research  Worker: Joseph M. Callus
Project Supervisor: ??
 

CPH14 STUDY ON THE QUALITY OF IRRIGATION WATERS

The lack of information on the water quality of irrigation waters in the local agricultural industry calls for a dire need to study various parameters of irrigation water. This project was intended to carry out a survey along the Maltese islands to study water quality trends in the Maltese water table. The variations in water quality will be considered not only on topographical and geomorphologic characteristics but also due to the effects of industry, drainage water and livestock in respect to growth of crops and public health. The study will also serve as reference data as to irrigation water quality. Moreover the effects of the parameters studied on the agricultural industry will be discussed in view of the European Union guidelines and limits particularly by studying the possible and major causes of nitrate pollution in groundwater either due to intensive use of fertiliser or from intensive animal husbandry.
The survey will be carried out on a representative sample approximately sixty taken from on site sources and considered as agriculturally intense regions will be tested for the following parameters namely: a. Electrical Conductivity- by conductivity meter in terms of total dissolved solids. This was then related with salinity. b. Chlorides- by titrimetry in terms of water salinity and classified accordingly according to USDA classification of irrigation waters. c. Sodium- by or atomic absorption spectrophotometry in terms of groundwater sodicity. Again the data obtained was classified according to sodicity levels. d. Nitrates- by steam distillation as total nitrogen. The levels were then treated with relation to location near farms or polluting sources and on type of irrigation water. e. pH- by a digital pH meter. The pH was studied in relation to nitrate content in waters f. Total hardness - by titrimetry in terms of calcium hardness and magnesium hardness.
The samples will be taken from boreholes, surface run off and man made reservoirs. Additionally the samples will be adequately labeled as to site location, point of sampling source, and date when sampled. The tests will be carried out at the public health laboratory at Evans Building Valletta.
Research  Worker: David Farrugia
Project Supervisor: Prof. Anthony Scicluna-Spiteri
 

CPH15 THE EFFECT OF SEA WATER IRRIGATION ON GROWTH AND SALT CONTENT OF ATRIPLEX HALIMUS L.

The effect on growth and nutrient content of Atriplex halimus L. using different concentrations of sea water is evaluated.
Atriplex halimus L., a perennial shrub found along the coastline around the Maltese Islands, garners its common Maltese name ‘Haxixa Mielha’ (saltbush), from the residual salt layer that forms on its leaves. This plant is of great interest because of its ability to survive and grow in saline and alkaline soils.
This halophytic shrub can tolerate high levels of salt in the soil and water and resist low and high environmental temperatures and droughts.  With its remarkable phytomass production and regrowth after browsing, and its relatively high crude protein, Atriplex halimus L. is a valuable protein supplement to nutrient deficient herbage on rangeland and in arid and saline regions.
A review of the aspects of the Atriplex halimus system is given. These aspects include the botanical characteristics such as leaf anatomy, leaf morphology and plant physiology with regard to the plant’s salt tolerance.
To assess the effect of salinity on growth and nutrient content, Atriplex halimus plants approximately 12-month old plants having a full-established root system, were used. These plants were grown under increasing salinity conditions and their growth rate was evaluated after a 4 and a half-month period.  A total of 5 sets of 12 plants per set were used. One set of the plants was used as the control and irrigated with distilled water throughout the experimental period. Each of the other 4 sets were irrigated with different treatment solutions having dilutions of 25%, 50%, 75% and 100% of sea water.
After the 4 and a half-month experimental period the relative growth rates, protein and mineral contents of the Atriplex plants were calculated. The following standard analytical parameters were determined: percentage crude protein, percentage minerals (ash) content and percentage of sodium, potassium, calcium, magnesium and chloride content
The growth soil medium, in which the experimental Atriplex halimus plants were grown, consisted of gravel and coarse sand.  A baseline for the following parameters of this growth medium (root-zone) was recorded:  pH, electrical conductivity, cation and anion content.
The Atriplex halimus plants performed equally well when irrigated with increasing salinity. The crude protein content was found to be relatively low (11.1% - 15.3%). The crude protein content increased from 11.1% in the plants irrigated with 25% seawater to 15.9% in those plants irrigated with the 100% sea water treatment. The ash content increased proportionally with exposure to increasing salinity treatments.  The percentage ash content ranged from 23.86% to 37.30%. The percentage sodium and chloride contents also increased with increasing salinity treatments. The potassium ion content also increased from 0.26% in the control to 5.67% in the full strength seawater. However it did not increase proportionally with increasing salinity irrigations The total percentage of calcium and magnesium content in Atriplex halimus ranged from 1.91% to 2.11%.
Research  Worker: Graziella Grech
Project Supervisor: Mr. George Attard
 

CPH16 THE NUTRITIONAL COMPOSITION OF ATRIPLEX HALIMUS L. IN MALTA

A study was conducted in order to determine the chemical composition of Atriplex halimus cuttings taken from Sliema (latitude 35º 54' 41" N, longitude 14º 29'54" E, altitude sea-level), the north coast of the Malta. The climate in Malta is semi-arid with an average annual precipitation of 605.6 mm, measured over ten years. The trial year was particularly humid, with a mean precipitation of 773.4 mm from September to February. Sampling was carried out on the 1st March 2000. The cuttings analysed were approximately eight weeks old and consisted of leaves and herbaceous stems with a leaf/stem ratio of 3.1:1 on a fresh weight basis. Crude fibre was analysed by the Weende process (acid/alkali double hydrolysis), crude protein by the Kjeldahl process, ash by calcination in a furnace at 600ºC, ether extract by extracting with diethyl ether, total dry matter oven drying at 105ºC for 16 hr and chloride using a chloride meter. Nitrogen-free extract was calculated by difference with the other components. The results were; CP 27.17 ± 0.55 %, Cl 7.88 ± 0.15 %, EE 2.62 ± 0.06 %, DM 17.59 ± 0.25 %, Ash 22.60 ± 0.28 %, CF 20.12 ± 0.03 % and NFE 27.50 ± 0.79%. All results are expressed on a DM basis, except DM which is expressed on a FM basis.
Research  Worker: Kristina Vella
Project Supervisor: Prof. Anthony Scicluna-Spiteri
 

CPH17 CULTURAL PRACTICES OF STRAWBERRY CULTIVATION IN MALTA

The strawberry is a popular small fruit in Malta.  Demand for strawberries has increased in the past years and is still growing.  A market for locally produced strawberries for fresh consumption surely exists.  This soft, juicy, nutritious, low calorific, bright red, slightly acidic, delicious fruit is sought for all year round by both the inhabitants and the ever increasing tourists that visit the island.  In response to the above, strawberry cultivation and thus production has been increasing year after year.
Major advances in the production were mainly achieved with the introduction of: new varieties, soil sterilization using methyl bromide, drip irrigation, cloches and mulching.
Strawberry varieties grown today are suitable for our local conditions of climate  and type of soil.  Plants are grown as annuals in Malta and are replaced every year to maintain yield and quality.  Methyl bromide is applied annually to suppress soil pathogens and reduce risk of disease.  Open field strawberry growers have adopted the annual plasticulture system and make use of plastic, usually black, for mulch.  The use of cloches and tunnels were another improvement.  Strawberries can also be grown in protected culture such as greenhouses.  Drip irrigation systems had also to be set up in order to enhance the yield of this non seasonal high cash crop.
Strawberry growers however do not produce strawberries exclusively but supply other fruits and vegetables mainly because the strawberry season is usually very short.  Research should be carried out as regards new methods and varieties to further extend the season and the yield.
In this study, different strawberry cultivation practices, carried out locally are compared so as to establish the strong and weak points of each and determine how the maximum yield can be achieved.  If the local yield of strawberries was to be increased, Malta, having a warm Summer and a short, mild, frost free Winter would be able to compete for foreign markets with an early good tasting crop either for fresh consumption or perhaps in a processed form.
Research  Worker: Sara Magro
Project Supervisor: Prof. Anthony Scicluna-Spiteri
 

CPH18 A SURVEY OF FUNGAL DISEASES ASSOCIATED WITH VITIS

A survey was carried out between July and September 2000 in 10 vineyards, 8 in Malta and 2 in Gozo to investigate fungal diseases of vines. Malta was divided into 2 sectors according to a map issued by the Works Department. Six samples were taken in sector 1 which represents central Malta, where the vineyards density is highest. The other two samples were from sector 2, representing southern Malta. Two other samples were taken from Gozo, represented by sector 3. Moreover samples were taken both from vineyards where traditional practices are used and vineyards where modern practices are employed. Field samples i.e. leaves, berries or stems infected by the fungi were immediately transferred to the Plant Health Laboratory at Marsa and stored in an insulated container so as not to kill any fungi. At the laboratory, the samples together with the instruments and working bench were sterilised with appropriate disinfecting solutions. Infected plant organs were first carefully examined under a stereomicroscope for the presence of any fruiting bodies and fungal hyphae, and thereafter sectioned and cultured to grow the fungus found inside the plant tissue section. Culture media such as water agar, potato dextrose agar and Czapek dox were used according to whether a general or specialised culture medium was needed. Culture media were prepared in the preparation room and sterilised by an autoclave. They were then left to cool slightly to a temperature of 45° C. The prepared agar suspension was carefully poured in petri dishes in equivalent quantities to a depth of 5 mm. They were left to solidify in a laminar flow cupboard and annotated appropriately. Infected plant tissues were thereafter placed on the agar and after some days the fungi were examined under both a stereomicroscope and a high power microscope. Fungal characteristics were noted and were compared with characteristics in fungal keys and when matching was completed the fungi were identified. The study identified 26 different fungi and 21 genera of which 22 fungi were found for the first time in the Maltese Islands. The percentage composition of the examined fungi was as follows: 10% obligate parasites, 29% facultative parasites and 61% saprophytes. The most common obligate fungi were powdery mildew and downy mildew. Some of the more important facultative fungi that were found in this study included Alternaria, Botrytis and Stemphylium. Saprophytes included Aspergillus, Acremonium and Stachobotrytis amongst others. At the end of the project a comparison of the traditional and modern vine cultivation practices was discussed. It was observed that traditional varieties like Girghentina and Gellewza were found in the fields of individual or part-time farmers whereas international varieties were found in the vineyards of large wineries. Moreover the intensity of diseases was much more pronounced in the traditional rather than in the modern way of trailing the vine. Finally a risk assessment of the potential fungal diseases for Malta was made. Diseases such as Phomopsis viticola, Botryosphaeria dothidea, Elsinoe ampelina and Pseudopezicula tracheiphila were identified as the diseases that pose great risk for Malta. It was concluded that the Plant Quarantine Section should be upgraded and its structures reinforced to prevent the entry of the above mentioned diseases.
Research worker: Matthew Tabone
Project supervisor: Dr. Antoine Vella

CPH19 STUDY ON PESTICIDE RESIDUES IN FRUITS AND VEGETABLES

The term pesticides includes insecticides, fungicides and herbicides together with rodenticides, nematicides, molluscides, and acaricides. These are agrochemicals designed to control the vari-ous attacks of pests in agriculture and horticulture.
Modern pesticides exert a systemic mode of action. They enter the plant's vascular system via its cuticle. Man's fight against pests dates back to ancient times, and we note various land-marks in history when pesticides were introduced. The introduction of Paris green and Bordeaux Mixture in 1800s to control the Colorado Beetle and other pests/ diseases led to the enactment of first law, in the USA in 1900, about pesticides. However it was not until the second world war that the revolutionary DDT was introduced. It was one of the first synthetic organochlorine. Later on a new generation organophosphates based on nerve gasses came into being. In 1959 both the FAO and the WHO then started to issue regular studies and regulations regarding pesticide use and their effects on man, animal and environment. Later on both organizations complied the concepts of ADI, MRL and GAP.
Pesticides have served to increase the world's food supply and decrease pests. However their environmental impact has generated controversy regarding their use. Today we note a de-mand for biologically grown foods. However still pesticides are being used to protect our crops. Thus the amount of pesticide used must be kept to a minimum so as to have the minimal residual levels possible in the crops we consume. We must not forget another factor that of pest and vector resistance to pesticides, which have given rise to new pesticides to be formulated.
The main aim of the study was to determine the presence or absence of any of the pesti-cides being investigated in a number of crops and fruits, both produced locally or imported but consumed locally. Detection of pesticide residue was done using ELISA kits supplied by the Institute of Agriculture at the University of Malta.
Twenty-four different samples were collected from different vegetable hawkers found in vari-ous places in Luqa, Zabbar, M'Xlokk, St. Paul's Bay, Zebbug, Mgarr (Malta), and B'Buga.
Any pesticide residue present was extracted in Methanol. During extraction 20 grams of finely chopped crop material was added to 1 00m1 of Methanol ANALAR grade. A 1:100 dilution in distilled water was then performed. The outcome was run as the sample on the plate.
The samples collected, were tested using three different Envirologix ELISA kits - Chlorpyrifos Kit, Metalaxyl Kit and the Synthetic Pyrethroid Kit. In these kits any pesticide residue present competes with enzyme (Horseadish-peroxidase)- labelled pesticide for a limited number of binding sites on the inner surface of the test wells. The outcome was visualized as a colour develop-ment step where sample concentration is inversely proportional to colour development.  He samples were run as two different trials. In Trial 1 samples 1-8 were tested whereas 16 other different samples were run during Trial 2.
For both trial crops and fruits were bought from different outlets - farmers and vegetable hawkers from different parts of the island. From a number of kilos, the various parts were taken to form the final kilo of sample material and then it was liquidized using a normal kitchen liquidizer. Then part of it was added to Methanol. It was then added to 20-30 grams of Anhydrous Sodium Sulphate. This was done to eliminate the extra water. Then a subsample was taken and added to 100 ml of distilled water. Again a subsample was taken and mixed with the materials provided with each kit before running the test plate on a reader to obtain the finals results.
The apparatus and materials used as well as the procedure followed varied according to the (;  kit being used.
The results obtained were entered in a database and the average absorbance determined. For all kits the %Bo was determined as:
% Bo = average GD of Calibrator or sample x 100 / average GD of Negative Control
A graph of % Bo (on the Y axis) against concentration (on the X axis) was plotted. After determining the values of the slope( m) and intercept (c), the value 'or the corresponding %Bo of each sample was calculated. The results were converted to parts per million (ppm) and compared to standards for each crop. Chlorpyrifos residues in potatoes (Cara type), cauliflower, apples (Sicily), strawberry, banana (Ecuador) and  Synthetic Pyrethroid residues in apples (Sicily) and apples (USA) were somewhat high when compared to the US Environment Protection Agency. The difference, however may be due to various factors. These may include a different pesti-cide testing positive with the ELISA kits. The values supplied by the EPA are those for the pesticide tested as indicated at the top of the list.
To verify the actual results which the ones obtained locally, one should have made an HPLC test to confirm that the pesticide is the same one indicated by the test kit or those which could be detected by the kit.
The test carried out show a difinite pattern of pesticide residue in all three kits. This is alarming even though the levels mostly bdo not exceed those established by the EPA. A mistake of evaluation by the farmer may lead him to use a double dose, thus exceeding the residue level.
This miscalculation may arise out of lack of knowledge of the fact that a pest or vector may adapt itself to a given pesticide, or that the pesticide was out dated even if bought recently. this is due to the fact that excess humidity or heat or excessive cold can disable the effectiveness of the pesticide.
Therefore it is recommended that in future pesticides should not only have clear (possibly in Maltese) indications on the way they should be used but also the time needed between each spraying session and other precautions which might be useful not to endanger the farmers health and the environment.
Research worker: Therese Visanich
Project supervisor: Dr. Antoine Vella & Dr. Everaldo Attard

CPH20 PESTICIDES AND PUBLIC HEALTH
This dissertation is intended to review current knowledge and thinking regarding the use (and abuse) of pest control methods in agriculture.
Throughout, the emphasis is made on the impact caused by these methods on individual health and the environment.
A review is made of the various methods, their efficacy or otherwise, and the harmful effects with reference to past incidents as well as long term effects.
The measures implemented to control these harmful effects are also discussed with reference to the international as well as the local situation; this includes legislation as well as alternative methods.
Finally the local situation is referred to with a recommendation for effective measures to ensure that the hazards of these necessary methods are controlled in the best possible manner.
Research worker: Helen Calleja
Project supervisor: Dr. Antoine Vella

CPH21 THE FUNGAL FLORA OF STORED ZEA MAYS L.
It is estimated that total postharvest losses of grains can be as high as 50% in some countries. Most result from infestation by insects, microorganisms, rodents and birds. A smaller but quite significant proportion of the total losses results from respiration and gradual deterioration of viability, nutritive quality, and end - use properties during storage.
The storage properties of grains are influenced by environmental conditions during growth and maturation, by the degree of maturity at harvest, by methods of harvesting, and by the handling the seed received until it is placed in storage.
Fungal deterioration of grain in storage is a dynamic process that involves a succession of microorganisms, the breakdown of organic matter and the generation of heat. Nutrients are lost because of changes in carbohydrates, proteins, lipids and vitamins. Functional properties, including germinability, are lost and aesthetic changes, including discoloration, caking and abnormal odours occur. Also, mycotoxins that elict a toxic response when damaged grain is ingested may be produced.
A total of about 60 - 65,000 metric tons of corn ( Zea mays L.) alone are imported annually from the American continent exclusively for animal feedstuff. Three separate batches of corn imported in Malta and stored in elavators at the Kordin Grain Terminal were being sold to breeders over the time span available.The aim of this study is to monitor the fungal flora on this stored corn, both that originating in the field before harvesting and that which grows mainly under storage conditions. Statistical analysis is used to determine whether the conditions of storage are altering the relative abundance of different fungal species. It is hoped that this monitoring regime can be used to better monitor the initial fungal load of the corn going into storage and successive changes occurring in the storage silos.
Research worker: Marie Bernadette Mallia
Project supervisor: Dr. Antoine Vella

 

CPH22 FUNGAL PATHOGENS OF THE PRUNUS SPECIES IN MALTA

The purpose of this project was to investigate the fungal diseases of the Prunus species. The investigation was carried out between July and September 2002. Ten samples were collected from ten different fields located in different localities as follows: three from Mgarr, three from Siggiewi, one from Rabat, one from Dingli, one from St.Lucija and from Ghammieri. The field samples, which were infected by the fungal pathogen, were immediately transferred to a plastic bag and stored in a refrigerator. These were then taken to the plant health laboratory for analysis microscopically to detect any fungal hyphae or fruiting bodies. These infected leaves were then sectioned and transferred on a culturing medium such as water agar. The medium was prepared in the laboratory by dissolving 15grams in 1000ml of distilled water. It was sterilised in an autoclave, left to cool to a temperature of 45⁰C and then poured in plastic sterilised petri dishes. After they solidified, the infected plant tissues were transferred on the agar plates for culturing. After one week they were examined under a high powered microscope and diagrams were made of the specimens identified. In all ten different fungi were identified through the use of fungal keys. The study revealed that the most common obligate pathogen was powdery mildew while the second most important was the shot hole disease.

Research worker: Alfred Buhagiar
Project supervisor: Dr. Antoine Vella
 

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