Environmental manipulation or conservation is one among several approaches evolved for harnessing the potentiality of entomopathogens in an integrated pest management. Cultural manipulation can permit the pathogen to reproduce more than usual or can preserve or enhance those already present. Among the key pest of chilli thrips, Scirtothrips dorsalis Hood (Thripidae: Thysanoptera) and broad mite, Polyphagotarsonemus latus [Banks] (Tarsonemoidea: Acari) are reported to cause the leaf curl in the leaves of chilli. Fusarium semitectum has infected the thrips and mites. The effectiveness of the mycopathogen, F. semitectum is chiefly influenced by the environmental conditions. Enhancing the microclimate the mycopathogen can be able to develop and buildup further. Chilli has been grown as sole crop, however companion crops such as sorghum, cotton, red gram, castor and maize were grown to understand the cropping system effect. Chillisorghum, chilli-cotton-chilli and chilli-red gram were the best cropping systems in terms of total chilli yield. The chilli-cotton-chilli cropping system ranked second with respect to benefit-cost ratio of 1:1 where as chilli-sorghum cropping system claimed the highest as 1.125:1. Interestingly, sorghum is not grown as a companion crop with chilli in Karnataka under rain fed conditions, where as chilli-cotton combination is a practice in many places of the state.

Foliar symptoms of web blotch were observed on some peanut cultivars (Arachis hypogaea L.) grown in the Kilinochchi district in the dry zone of Sri Lanka during October 1993 to January 1994, following heavy rains (mean relative humidity 79 to 85%, mean temperature 25 to 27°C). Severe symptoms appeared on peanut cultivars ICGS 11 and ICGS 121. Cultivar ICGS 11 belongs to the Spanish group (A. hypogaea subsp. fastigiata var. vulgaris) and ICGS 121 belongs to bunch type (A. hypogaea subsp. hypogaea var. hypogaea). Initial symptoms of small, irregular, brown to reddish brown lesions along the midrib of both young and old leaves were observed. Large, nearly circular tan or dark brown blotches appeared on the adaxial surface of the leaves. Older lesions became dried and cracked. Lesions on the abaxial surface were pale brown, and less pronounced. These observations correlate closely with those made by Taber (2). Severe defoliation was observed in the infected fields of Spanish cultivars. Phoma arachidicola Marasus, G. D. Pauer, & Boerema was consistently isolated from symptomatic tissue. Colonies on potato dextrose agar were at first creamy white, and flattened with little aerial growth. Colonies eventually turned dark brown with a wide appressed margin. All isolates produced pale to dark brown and globose pycnidia. Dark-colored, globose, beaked pseudothecia were also observed in cultures, as reported by Subrahmanyam et al. (1). Dark-colored, round, single-celled pycnidiospores measuring 4 to 9 × 2.5 to 4 µm were observed in culture. The fungus was inoculated onto the leaves of 10 healthy plants of each cultivar and another 10 plants were maintained as uninoculated controls. All plants were covered with polypropylene bags to increase the humidity. Plants inoculated with the fungus produced symptoms 7 to 9 days after inoculation similar to those observed in the field. None of the control plants showed any disease symptoms. The fungus was reisolated from the diseased leaf tissue. Microscopic examination confirmed the identity of the fungus and satisfied Koch's postulates. All cultivars were then grown under irrigation during February to May 1994 (mean relative humidity 60 to 70% and mean temperature 32 to 35°C). No disease symptoms were observed, indicating that the proliferation of P. arachidicola on Spanish cultivars was influenced when the crop establishment period coincided with low air temperature (25 to 27°C) and high relative humidity (79 to 85%). This is the first report of web blotch in Sri Lanka and its occurrence was confined to the dry zone areas of the country. References: (1) P. Subrahmanyam et al. 1994. Web blotch disease of groundnut. Inform. Bull. No. 43, ICRISAT; and Peanut Collaborat. Res. Support Prog. (2) R. A. Taber. Web blotch. Pages 9–10 in: Compendium of Peanut Diseases. D. M. Porter, D. H. Smith, and R. Rodrigues-Kabana, eds. American Phytopathological Society, St. Paul, MN, 1984.

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Root-knot nematode, Meloidogyne incognita (Kofoid and White) is a major threat to chilli (Capsicum annum) cultivation, by forming root galls and subsequent wilting. These nematodes live in soil, roots debris and reported surviving in other Solanaceae crops. Chemical application of nematicides cause impact on environment, therefore biocontrol using antagonistic fungi is desired to tackle this problem. This research is aimed to evaluate the effect of Trichoderma viride and its formulations on management of M. incognita. Oil cakes such as neem (Azadiracta indica), gingelly (Sesamum indicum), Mahua (Madhuca longifolia) and garlic (Allium sativum) extracts were used to evaluate the growth and sporulation of T. viride. Chilli variety MI-2 was used. Among the four preparations, neem oil cake recorded high spore yield of 1.75 ×107 spores/ml. Similarly gingelly oil cake and garlic produced the spore yields of 1.57 ×107 spores/ml and 1.368 ×107 spores/ml, respectively. Comparatively Mahua oil cake obtained low spore yield of 7.87×106 spores/ml. Plant growth was significant (P<0.05) in the application of neem oil cake formulation (30.42 cm). Extent of galling was significantly low with garlic (9.00) and neem (9.25). These results confirmed that the formulations of neem, gingelly oil cake extracts and garlic aqueous extract stimulated the chilli plant growth, productivity and reduced the nematode infestation. Above all, neem oil cake and garlic are the best formulations that can be used to manage M. incognita

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Papaya (Carica papaya L.) is an economically important orchard crop, mainly cultivated in tropical and sub-tropical countries. Due its excellent medicinal value, papaw is recommended for daily consumption by medical professionals as fresh fruit. Papaya production is being hampered by papaya Anthracnose disease, caused by Colletotrichum gloeosporioides, which is inflicting major economic losses of around 40–100% during field cultivation, transportation, and storage in organic agriculture. An investigation was planned to assess the antifungal capacity of the medicinal plants Spinacia oleracea, Limonia acidissima, Allium sativum, Achyranthes aspera, Calotropis gigantea, Ocimum basilicum, Mukia scabrella, Ficus racemose, Azadiracta indica, Ocimum tenuiflorum, Lantana camara and Ocimum cinnamon combined with bee wax coating against papaya anthracnose disease. Fifty-percent concentrations of botanical were extracted from dried leaves using a methanol-based solvent extraction method. Two sets of partially ripened non-infected marketable papaya fruits were collected and treated with 50% concentration of botanical extracts and allowed to dry. One set was coated with melted wax by spraying under cool conditions using a power sprayer, along with a non-treated control. These experimental setups were arranged in a complete randomized design with five replicates. Four hours after wax coating, both sets were inoculated with spores of C. gloeosporioides. Data on disease incidence, disease severity (0–5 scale), number of days for disease-free period, pH, and TSS were measured in both sets and ANOVA was performed using SAS software. Duncan’s Multiple Ranges Test (DMRT) was used to determine the least significant differences among the treatments at p < 0.05. The results show that disease incidence and severity in O. basilicum + bee wax treated fruits was 0% and 5%, respectively, and significant at p < 0.05 until the 10th day post-inoculation; thereafter, disease incidence and severity were slowly increased to 15% on the 14th day post-inoculation, but in other treatments and the control, disease incidence and severity varied from 60–80% and 100%, respectively, from the fifth day post-inoculation. Moreover, bee wax-coated papaya fruits showed significantly higher preserved days, to a maximum of 17.047 ± 3.86. Weight loss percentage, pH and TSS were not significantly on par among wax-coated treatments but were significant when compared with wax-free treatments. This study concludes that the combined application O. basilicum + bee wax is a promising alternative to nasty fungicides.

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