An investigation was conducted for the management of root knot nematode Meloidogyne incognita (Kofoid and White) Chitwood infesting tomato through the application of bio-control agent like Bacillus subtilis, Trichoderma harzianum and Pseudomonas fluorescens. Experiment result revealed that minimum no. of galls/25seedlings (17.50) and maximum seedling height (27.6cm) were observed in Bacillus subtilis @50g/m2 in nursery bed + B. subtilis @ 5kg along with 2.5 tons of FYM/ ha. The highest weight/25seedlings (69.50g) was noticed in the B. subtilis @50g/m2 in nursery bed + B. subtilis 2.5kg along with 2.5 tons of FYM/ha. The highest growth of the plant at 45 DAT (49.2cm) and at harvest (81.2cm) and maximum fresh (711.3g) and dry weight (265g) was found in B. subtilis @50g/m2 in nursery bed + B. subtilis 2.5kg along with 2.5 tons of FYM/ha. B. subtilis @50g/m2 in nursery bed + B. subtilis 2.5kg along with 2.5 tons of FYM/ha exhibited lowest gall index (1.2/plant) and highest reduction of nematode population and provided highest yield of tomato fruits (335.75q/ha).
Laboratory experiment was conducted to study the biology of coccinellid predators from agroecosystems of Odisha. About 17 species were identified, the most important being Coccinella septempunctata, Coccinella transversalis and Cheilomenes sexmaculata predating on aphids infesting cowpea. The biology of these when evaluated indicated that C. septempunctata was the largest, and C. sexmaculata the smallest; grubs of all the three are susceptible to the rising temperature. The total developmental period was maximum during January and the least during May for all species. Total larval period was 11.9 ± 2.34, 12.1 ± 6.19 and 12.6 ± 0.01 days in January and 8.2 ± 0.07, 7.00 ± 0.01 and 7.9 ± 0.06 during May with C. septempunctata, C. transversalis and C. sexmaculata, respectively; developmental periods for these were observed to be 22.4 ± 0.67, 20.2 ± 1.46 and 17.4 ± 0.82 days during January, and 15.2 ± 0.01, 11.5 ± 0.39 and 12.3 ± 0.61 days during May, respectively. Prepupae and pupae were the least affected by the fluctuations in temperature.
Aim: To evaluate the comparative parasitic efficiency and biology of Trichogrammatid wasps on noble laboratory host Corcyra cephalonica as well as on Helicoverpa armigera, the cosmopolitan, polyphagous and precarious insect pest of many cultivated crops. Methodology: The biology of Trichogramma chilonis and T. japonicum, their sex ratio, and parasitic efficiency were studied. Host insects were reared on artificial diet to obtain their eggs for initiating the experiment. Egg-card pieces were prepared with the irradiated eggs of respective host insects. Egg-cards were introduced into the tubes containing freshly emerged adult parasitoids. Parasitized egg-cards (Trichocards) were kept separately in plastic tube to study the biological attributes and percent parasitization of the parasitoids. Egg cards of different host eggs taking eggs of different age groups were prepared to study the effect of age of host eggs on the biological efficiency of the parasitoids. Results: Irrespective of Trichogramma species, the duration (d) of eggs to adult period was more when reared on the eggs of H. armigera than on the eggs of C. cephalonica. Maximum life stage duration of T. chilonis and T. japonicum from egg to adult was 8.2 days and 10.2 days, respectively, when reared on H. armigera eggs. There was maximum parasitization (84.8%) of fresh eggs of C. cephalonica by T. chilonis as compared to the egg parasitization of 73.4% by T. japonicum. Likewise, extreme parasitization of fresh eggs of H. armigera was recorded as 62.4% when parasitized by T. chilonisas against 59.7% parasitization by T. japonicum. Interpretation: According to the study, H. armigera eggs have the finest biological and parasitic features in terms of the highest adult longevity, sex ratio, mean progeny female-1, and mean adult egg-1, making them the best for mass production of the egg parasitoids, T. chilonis. Key words: Corcyra cephalonica, Host eggs, Helicoverpa armigera, Parasitization, Trichogramma
As silicon is known to have a positive role in enhancing the resistance of rice plants to insects, an investigation on one aspect of the biochemical and molecular basis of rice plant defences mediated by silicon amendments against brown plant hopper Nilaparvata lugens (Stål), comprising eld, pot culture and laboratory experiments was undertaken in OUAT. Two organic products; Diatomaceous Earth (DAE) at 0.15, 0.30 and 0.45 t/ha, and Rice Hull Ash (RHA) at 2, 3, 4 t/ha, along with one inorganic source, calcium silicate (CaSiO 3 ) at 2, 3, 4 t/ha were soil applied as basal to evaluate their effects on the accumulation of silicon, proline, phenol, carbohydrates and protein in the plant tissues along with proteomic and Scanning Electron Microscope (SEM) studies. Results showed decreasing in proline and protein contents and increasing in silicon, phenol and carbohydrates contents in infected Si amended plants as compared to the control. Proteomic study showed appearing of a thick band of about 20 KDa in infested plants indicating its role in defense mechanism. Under SEM, the dumbbell shaped deposits of Si were marked clearly at different doses of silicon, indicating that the increase in silica dose enhanced its deposits, which was supported by EDAX-SEM data. Results of this study clearly demonstrated that soil amendments with silicon through organic and inorganic sources effectively caused biochemical and molecular changes that ultimately support the plant defenses against BPH.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.