ARI Biennial Review for 2018-2019

PLANT PROTECTION Scientific work in Plant Protection concern research studies in Plant Pathology and Entomology. Specialised studies are conducted to address major crop protection problems associated with particular virus and virus- like diseases, prokaryotic microorganisms and insect pests. Joint multi-disciplinary research projects are undertaken, targeting various important pests and diseases of cultivated vegetable and fruit tree crops. All research activities are governed by the considerations of sustainability in crop protection and production, food quality and safety, environmental protection and the utilisation of new technologies for the development of more effective crop protection practices. Plant Pathology research includes the implementation of modern nucleic acid diagnostic assays for plant pathogens. Research effort has been focused on the development of effective detection tools in order to identify the phytosanitary status of plants, for certification and quarantine purposes. In line with the above principles, one of the main activities of the Section concerns the development of integrated pest management (IPM) strategies, based on various combinations of ecosystem-oriented methods, i.e. biological control, cultural practices, natural products, resistant varieties, resistant rootstocks and minimal use of selected, mild pesticides. This approach ensures sustainability and minimises pesticide risk to human health and the environment. It can be applied alone or in combination with other ecosystem-oriented production practices, in the context of an advanced system of sustainable agriculture, known as integrated crop management (ICM). Studies to develop IPM/ICM systems were carried out on citrus, grapevines and on vegetable and ornamental greenhouse crops, in cooperation with other Sections of the Institute. Plant Pathology and Entomology laboratories provided support for the scientific identification of plant diseases and insect pests, in various samples provided by the Department of Agriculture, the Medical and Public Health Services, the Department of Forestry, agriculturists from the private sector and farmers. PLANT PATHOLOGY Programme for the control and characterisation of Citrus tristeza virus The programme for the control of CTV was initiated in 1992, with main aims the systematic survey of all citrus and the removal of infected trees and/or groves wherever that was feasible. The survey has been conducted by indexing 10-20% of the trees of each grove and samples were tested in the Plant Virology Laboratory by Enzyme- linked immunosorbent assay (ELISA). Disease incidence ranged in the different districts from 2.33% to 18.3%. The highest proportion of infected trees and groves was noted in the districts of Ammochostos and Lemesos. Field symptoms of CTV-infected trees varied from mild to severe, while some infected trees were symptomless. The most intense symptoms were noted on Marsh seedless or Star Ruby grapefruit and included stunting, chlorosis, fragility and dieback of twigs, pitting of branches and general decline. CTV caused severe decline and death of 40 to 50-year-old grapefruit and Valencia orange trees in certain groves in the districts of Ammochostos and Lemessos. With regard to the greenhouse indexing tests, 40 PLANT PROTECTION