An investigation on the toxicity of two biopesticidal plants – Carica papaya and Nerium oleander aqueous leaf extracts to Oreochromis mossambicus. The LC50 value of Carica papaya and Neriumoleander aqueous leaf extracts was 700 ppm and 400 ppm respectively. The sub lethal concentration for C. papaya and N. oleander was 70ppm and 40ppm respectively. The fishes wereexposed to the sub lethal concentration for a period of 14 days. At the end of 7th and 14th day thefishes were dissected and the gill, liver and intestine were removed from exposed and control groupfishes. The tissues were processed and sectioned at 4µm and then were stained with Haematoxylin- Eosin. The observation of the slides was done under light microscope at 40x magnification andphotographed. The exposed group showed histopathological changes in the tissues, such as: shrunken and narrow secondary gill lamellae, mild to moderate infiltration of inflammatory cells inthe primary and secondary gill lamellae, vacuolar degeneration of epithelial cells of intestinal villi, massive infiltration of inflammatory cells throughout the base of the villi and disruption of epithelial cells. The liver showed swollen nucleus, hydrated and vacuolar degeneration of hepatocytes and mild pockets of infiltration of inflammatory cells.

The ethyl acetate extracts of the culture of Eupenicillium parvum, Gelasinospora brevispora, Neosartoryap seudofischeri, N. quadricincta and N. multiplicata were assessed for their antifungal activity against ten economically important plant pathogenic fungi: Pythiumaphanidermatum, Phytophthorapalmivora, Alternaria sp., Fusariumoxysporum, Colletotrichumgloeosporioides, Lasiodiplodiatheobromae, Helminthosporiummaydis, Sclerotiumrolfsii and Rhizoctoniasolani,which arecausative agents of fruit and vegetable diseases. The bioassay for the antifungal activity of the fungal crude extracts was based on the dilution plate method. Although all the extracts exhibited a complete inhibition of the mycelial growth of some plant pathogenic fungi at the highest concentration tested (10,000 ppm), an interesting antifungal effect was observed for the crude extract of N. pseudofischeri KUFA 0060 against Ph. palmivora and C. capsiciat 100 ppm, as well as for N. quadricincta KUFA 0064 against Ph. palmivora and Alternaria sp. at 10 ppm. The results obtained from this screening allow us to identify new potential sources for the development of alternative fungicides.

A field trial was conducted in kharif seasons of 2011-2012 to study the efficacy of certain entomopathogens viz., Beauveria bassiana, Metarhizium anisopliae,Verticilium lecanii, Bacillus thuringiensis var. kurstaki @ 5 g/l along with standard check - Quinalphos 25 EC @ 1.5 g/L and Spinosad 45%SC @ 73 g a.i. /ha against lepidopteran defoliators. Bacillus thuringiensis @ 1013 spores/ha followed by B. bassiana @ 1013 spores/ha were the most effective treatments when applied as foliar sprays at 38, 41 and 45 days old crop. These treatments were effective in reducing the foliage feeder larval population. The highest grain yield was obtained also in the treatment, B. thuringiensis var. kurstaki (474.77 kg/ha). The lowest yield was recorded in the control (215.23 kg/ha) which was significantly inferior to the rest of the treatments.

A field experiment was conducted at the Eastern farm of Pandit Jawaharlal Nehru College of Agriculture and Research Institute (PAJANCOA and RI), Karaikal during Rabi 2013 to study theeffect of newer insecticides to natural enemies of rice pests. Two foliar applications were carriedout at an interval of fifteen days after leaf folder larvae reached economic threshold level. Theresults showed that the overall mean population of coccinellids was found to be more in theuntreated check (1.28 and 1.55/hill) followed by indoxacarb 14.5 SC at 72.50 g a. i. / ha (0.99and 1.12/ hill) in the first and second foliar application. The overall mean population of spiders was high in the untreated check (1.40 and 1.59/ hill), followed by indoxacarb 14.5 SC at 72.50 ga. i. / ha (1.07 and 1.07/ hill) over the other treatments.

The aim of this study was to evaluate plant extracts for antifungal activities against Phythopthorainfestans (Mont.) de Bary, an important pathogen of potato which causes late blight disease. Acetone, ethyl acetate and water extracts of garlic (Allium sativum L.), Pawpaw (Carica papaya), Neem (Azadirachta indica), Mexican marigold (Tagetes minuta) and peri –winkle (Vinca rosea) were screened in vitro for their antifungal activities against Phythopthora infestans using the discagar infusion and microtitre doubledilution techniques. The same extracts were then tested for antifungal activity in vivo in the greenhouse on inoculated potato plants. The water extracts of Allium sativum and Azadirachta indica were active against Phythopthora infestans and had aminimum inhibitory concentration (MICs) of 1.65 mg/ml. MICs of Allium sativum, Azadirachtaindica and Tagetes minuta acetone extracts were 0.78, 3.13 and 6.5 mg/ml respectively against Phytophthora infestans. Allium sativum and Azadirachta indica water and acetone extracts performed well and they effectively reduced potato late blight in the greenhouse. These extracts compared well with the reductions due to application of Ridomil, a synthetic fungicide applied at 42.5g/l (active ingredient) and also with levels in the non-inoculated control. Allium sativumandAzadirachta indica were effective both in vitro and in vivo in controlling late blight have a potential to be used as fungicides against the disease. The plants are readily available and the extractionmethod is also simple and could lead to high adoption as fungicides by resource poor farmers.