Detection and molecular characterization of viruses associated with tomato yellow leaf curl disease in cucurbit crops in Jordan

In this study, Tomato yellow leaf curl Sardinia virus (TYLCSV) and the strains Israel and Mild of Tomato yellow leaf curl virus (TYLCV-IL, TYLCV-Mld) were detected for the first time in four cucurbit crops in Jordan by nested polymerase chain reaction (nPCR). These viruses cause the tomato yellow leaf curl disease (TYLCD) in tomato. Cucumber, squash, melon and watermelon plants inoculated with TYLCV-IL[JO:Cuc], TYLCV-Mld, TYLCSV-IT[IT:Sar:88] and the Jordanian isolate of TYLCV (TYLCV-JV) did not show disease symptoms. However, virus-specific fragments were detected in uppermost leaves of symptomless plants by nPCR. A whitefly transmission test showed that Bemisia tabaci could transmit TYLCV-Mld from cucumber into tomato and jimsonweed plants. However, all infected tomato plants remained symptomless. In addition, results of semi-quantitative PCR (sqPCR) analysis showed that the relative amount of TYLCV-Mld DNA acquired by B. tabaci from cucumber plants was less than that acquired from tomato plants.     

Phelipanche aegyptiaca management in tomato

Phelipanche and Orobanche species (broomrapes) are root holoparasitic plants that cause severe damage to economically important crops. Phelipanche and Orobanche spp. are widespread in Mediterranean areas, in Asia and in Southern and Eastern Europe, attacking dicotyledonous crops and depending entirely on their hosts for all nutritional requirements. Phelipanche aegyptiaca , Phelipanche ramosa and Orobanche cernua are extremely troublesome weeds on tomatoes. These noxious parasites exert their greatest damage prior to their shoot emergence and flowering; therefore, the majority of field loss may occur before diagnosis of infection. This review summarises the four main control measures for the weedy root parasites Phelipanche and Orobanche in tomato, namely chemical and biological control, resistant varieties and sanitation. Some of these methods are commercially widely used by farmers in Israel (chemical control), some are in the final stages of development towards commercialisation (resistant varieties and sanitation), and some still require further development and improvement before commercial implementation (biological control). The review presents an up-to-date summary of the available knowledge on their use for broomrape management in processing tomatoes.     

Parasitoid control of the tomato fruitworm,Helicoverpa armigera,in smallholder farmer fields in Senegal

In Africa, Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae) is a key pest of cotton and vegetable crops, particularly tomato. Alternatives to insecticides to control this pest are needed such as conservation biological control. However, knowledge on the diversity and ecology of naturally occurring enemies of H. armigera is limited. A two-year field survey was conducted in a set of tomato farmer fields in the main vegetable-growing area in Senegal (Niayes) to assess the spatial and seasonal occurrence of indigenous parasitoids of H. armigera, and to evaluate the effect of insecticide use on biological control efficiency. No parasitoid emerged from H. armigera eggs. Incidence of larval parasitoids was generally moderate (20%) but highly variable (0%–100%) among fields, independently of host abundance, and negatively affected by the number of insecticide applications. Larval parasitism was largely dominated by the larval parasitoid Meteorus laphygmarum Brues (Hymenoptera, Braconidae), but a positive correlation was found between specific richness or Shannon diversity index of the parasitoid community and parasitism rate. This study is a first step toward development of research and extension programs for conservation of natural enemies in the framework of integrated management of the tomato fruitworm in Senegal.     

Natural enemy‐mediated indirect interactions among prey species: potential for enhancing biocontrol services in agroecosystems

Understanding how arthropod pests and their natural enemies interact in complex agroecosystems is essential for pest management programmes. Theory predicts that prey sharing a predator, such as a biological control agent, can indirectly reduce each other's density at equilibrium (apparent competition). From this premise, we (i) discuss the complexity of indirect interactions among pests in agroecosystems and highlight the importance of natural enemy‐mediated indirect interactions other than apparent competition, (ii) outline factors that affect the nature of enemy‐mediated indirect interactions in the field and (iii) identify the way to manipulate enemy‐mediated interactions for biological control. We argue that there is a need to increase the link between community ecology theory and biological control to develop better agroecological methods of crop protection via conservation biological control. In conclusion, we identify (i) interventions to be chosen depending on agroecosystem characteristics and (ii) several lines of research that will improve the potential for enemy‐mediated indirect interactions to be applied to biological control. © 2014 Society of Chemical Industry     

The Development and Status of Biologically Based Integrated Pest Management in Cuba

This paper describes the evolution of IPM in Cuba during three pre- and post-revolutionary periods. The state of the art of IPM after the collapse of Cuba's relations with the soviet block is analyzed in detail. During this 'special period' Cuba is undergoing a major conversion from conventional agriculture dependent on external inputs to a semi-organic agriculture dependent on local resources and low external inputs. The massive production and use of microbial pesticides complemented by cultural and habitat management techniques are at the heart of this new quest of agricultural sustainability in the midst of the economic crisis. About 982,000ha of various crops are under biological control, with savings of about US$ 30 million in pesticide imports.     

Harmonious interaction of kaolin and two insect predator species in plant protection

Lacewings and lady beetles represent two important groups of natural enemies for pest control. Kaolin is used in various crop ecosystems to reduce abiotic plant stressors and pest colonization. Compatible methods aimed at reducing abiotic and biotic plant stressors are desired in crop management systems. Therefore, this work evaluated the development and survival of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) and Eriopis connexa (Germar) (Coleoptera: Coccinellidae) larvae of different ages treated with kaolin at three different concentrations (ca. 60, 80, and 100 g/L) and prey consumption when treated with kaolin at a field rate of 60 g/L. The prey used were the whitefly Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) and the aphid Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae). Survival rates and development durations for E. connexa larvae topically treated with kaolin at different ages were similar to those for untreated larvae. However, larvae of C. externa reduced survival and delayed development when treated with kaolin concentrations greater than the recommended field rate. Otherwise, kaolin treatments did not affect prey consumption by larvae and adults of both predator species.     

Populations of predators and parasitoids of Bemisia tabaci (Hemiptera: Aleyrodidae) after the application of eight biorational insecticides in vegetable crops

BACKGROUND: The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is an important pest of vegetables and many other crops worldwide. Eight biorational insecticides (based on oil, plant derivatives, insect growth regulator and fungus) were evaluated in the field for their influence on populations of six natural enemies of B. tabaci. Natural populations of two predators [Chrysoperla carnea Stephen (Neuroptera: Chrysopidae) and Orius spp. (Hemiptera: Anthocoridae)] and two genera of parasitoids [Encarsia spp. and Eretmocerus spp. (Hymenoptera: Aphelinidae)] were evaluated in eggplant (Solanum melongena L.). Also, augmented field populations of three predators [C. carnea, Coccinella undecimpunctata L. (Coleoptera: Coccinellidae) and Macrolophus caliginosus (Wagner) (Hemiptera: Miridae)] were evaluated in cabbage (Brassica oleracea var. capitata L.), cucumber (Cucumis sativus L.) and squash (Cucurbita pepo L.). RESULTS: Regardless of natural enemy or crop, jojoba oil, Biovar and Neemix had the least effect on abundance of the natural enemies in comparison with the other insecticides during a 14 day evaluation period. Conversely, Admiral, KZ oil, Mesrona oil, Mesrona oil + sulfur and natural oil had a high detrimental effect on abundance of the natural enemies. CONCLUSION: These results demonstrate the differential effects of biorational insecticides for whitefly control on predators and parasitoids in the field. Published 2011 by John Wiley & Sons, Ltd.     

Insect pests and their management in yam production and storage: a world review

Yam (Dioscorea spp.) is a tropical tuber crop produced for food and medicinal purposes. Yams are infested by a broad taxonomic diversity of insect pests. We reviewed a total of 73 insect species associated with Dioscorea species in different parts of the world. Yam is infested by 48 species when the crop is in the field, and after harvest (i.e. in storage) the tubers are attacked by 27 species. The majority of these insects belong to the order Coleoptera (35 species) followed by the orders Hemiptera (15), Lepidoptera (13), Isoptera (5), Hymenoptera (2), Diptera (1), and Thysanoptera (1). Yam scales, mealybugs, and a few beetles cause significant losses to tubers both in the field and in storage. We review various methods of management for these insect pests. An integrated approach towards managing these pests, both in the field and in storage, is essential. Post-harvest losses in storage of yam can be reduced, partly, by using biocontrol agents for mealybugs and scales. Alternative strategies for the management of insect pests of tubers in storage are discussed.     

The efficacy of spinosad against the western flower thrips, Frankliniella occidentalis, and its impact on associated biological control agents on greenhouse cucumbers in southern Ontario

Insecticides are the most commonly used tactic to control western flower thrips (WFT), Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), on greenhouse cucumber. However, WFT has developed resistance to several of the insecticides presently in use. In addition, some of these insecticides adversely affect greenhouse biological control agents used to control WFT, resulting in subsequent pest resurgence. Therefore, there is a need to identify novel insecticides with unique modes of action for use in integrated pest management (IPM) programs to effectively control WFT with minimal impact on associated biological control agents. In laboratory bioassays conducted in 2001, immature and adult WFT and three associated greenhouse biological control agents: Amblyseius cucumeris Oudemans (Acarina: Phytoseiidae), Orius insidiosus Say (Hemiptera: Anthocoridae) and Encarsia formosa Gahan (Hymenoptera: Aphelinidae) were exposed to direct, direct/residual, and residual contact applications of the novel biopesticide, spinosad (Conserve 120 SC), and the industry standard for whitefly control, endosulfan (Thiodan 50 WP). In all three types of assay, spinosad was effective against immature and adult WFT life stages. It showed low toxicity to A. cucumeris, moderate toxicity to O. insidiosus and high toxicity to E formosa. Greenhouse studies involving exposure of immature and adult WFT and adult biological control agents to cucumber leaves sprayed previously with spinosad supported the laboratory data. Spinosad showed low toxicity to A. cucumeris exposed to leaves 1 day after treatment (DAT), moderate toxicity to O. insidiosus 1 and 8 DAT, and high toxicity to E. formosa up to 28 DAT. These data, along with spinosad's unique mode of action, suggest it would be a valuable reduced-risk control agent for greenhouse cucumber IPM programs.