Comparative virulence of strains of entomopathogenic nematodes for management of eggplant Grey Weevil, Myllocerus subfasciatus Guerin (Coleoptera: Curculionidae).

The Grey Weevil, Myllocerus subfasciatus Guerin, is an important emerging pest of quarantine significance in Solanaceae crops including the eggplant, Solanum melongena. Entomopathogenic nematodes (EPNs) have been shown to be a potential source of safe and effective control of M. subfasciatus. In this study, we determined the virulence of seven strains of EPNs (Nematoda: Rhabditida) viz. Heterorhabditis bacteriophora NBAIIHb105, H. indica NBAIIHi101, H. indica NBAIIHiMah, Steinernema abbasi NBAIISa01, Steinernema abbasi NBAIISa04, S. carpocapsae NBAIISc04 and S. glaseri NBAIISg01, with different foraging behaviour, against larvae of eggplant grey weevil, M. subfasciatus (Coleoptera: Curculionidae), and their suitability in five representative soils from the eggplant grown areas under laboratory conditions. All seven nematode strains caused >80% mortality of M. subfasciatus larvae at 40 IJs/cm2. LC90 values ranged between 21.18 and 46.41 IJs/cm2 at 96 h post-application, which corresponded to field concentrations between 2.1-4.6×109 IJs/ha. H. indica NBAIIHi101, S. glaseri NBAIISg01, S. abbasi NBAIISa01 and S. carpocapsae NBAIISc04 recorded higher grub mortality, compared to H. indica NBAIIHiMah, H. bacteriophora NBAIIHb05 and S. abbasi NBAIISa04 indicating existence of inter- and intra-specific variation in virulence. Response Surface Modelling (RSM) optimized LC and LT values for maximised larval mortality. RSM predicted a concentration of 58.05-62.54 IJs/cm2 of these EPN (corresponding to a field dose of 5.8-6.2×109 IJs/ha) required for effecting 97.10-99.67% grub mortality, at 90-97 h of exposure. EPN strains performed better in terms of larval mortality in loamy sand, alluvial, mountain soil, red laterite compared to black cotton soils. Efficacy of EPN was positively correlated with the content of sand, and negatively with the clay content. It is possibly the first report that established the potential of local strains of EPNs with different foraging ability and their dosages for suppression of subterranean root feeding larvae of M. subfasciatus in five broad soil types of eggplant grown areas. Validation of this baseline data in real-time eggplant crop situations may help in evolving EPN-based viable management schedules for M. subfasciatus.

Developing novel bacterial based bioformulation having PGPR properties for enhanced production of agricultural crops.

Plant growth promoting rhizobacteria (PGPR) are beneficial rhizobacteria which enhance plant growth as well as the productivity by a variety of mechanisms. PGPR were isolated from the rhizosphere region of som plants (Machilus bombycina King) maintained at the Central Muga Eri Research and Training Institute, Lahdoigarh, Jorhat. A bacterial based bioformulation was prepared and sprayed over the experimental crops including tomato (Solanum lycopersicum), cauliflower (Brassica oleracea var botrytis), chili (Capsicum annuum) and brinjal (Solanum melongena). Biochemical analysis was done on these PGPR treated crops as well as the untreated crops. The bioformulations prepared from Bacillus cereus (MTCC 8297), Pseudomonas rhodesiae (MTCC 8299) and Pseudomonas rhodesiae (MTCC 8300) was found to be the most effective in increasing the shoot height, number of leaves, early fruiting and total biomass content of the plants after treatment.

Molecular characterization of brinjal shoot and fruit borer, Leucinodes orbonalis (Guenée) (Lepidoptera: Crambidae) based on mitochondrial marker cytochrome oxidase I and their phylogenetic relationship.

Shoot and fruit borer, Leucinodes orbonalis is an important insect pest infesting brinjal or eggplant in India. Molecular characterization of nine different populations belonging to various brinjal growing regions was done using Cytochorome C Oxidase I (COI) gene. Nucleotide analysis of genetic diversity and phylogenetic analysis of the COI indicate that the L. orbonalis from different geographical regions are homogenous. The results showed less nucleotide diversity (π = 0.007895) and overall mean distance (0.008±0.003). Topologies of neighbour-joining (NJ) trees indicate all the populations belong to single major clade. Therefore, it is inferred that there was no significant molecular diversity within L. orbonalis of different geographical locations of India with respect to COI.

Incidence of Henosepilachna Vigintioctopunctata Fab. on Brinjal in Eastern Uttar Pradesh.

Field trial was conducted to study the seasonal incidence and influence of abiotic and biotic factors on Henosepilachna vigintioctopunctata of brinjal during 2011-12.The incidence of H.vigintioctopunctata started during first week after transplanting with a mean population of 0.81 per planton brinjal crop. The peak incidence was observed during the third week of October with a mean population of 6.98 per plant and the incidence decreased gradually up to crop maturity. Data recorded on effect of abiotic and biotic factors on H.vigintioctopunctata population revealed that the incidence had non-significant relation with a biotic factors like minimum temperature, evening relative humidity and significant relationship with maximum temperature, morning relative humidity and rainfall. The pest population also shows positive and significant correlation with biotic factors like coccinellid beetles as well as spiders.

Genetic Variability and Correlation Studies in Brinjal (Solanum Melongena L.).

The present investigation was conducted at Department of Horticulture, Horticulture Garden, Dr. PDKV, Akola (M.S.), during kharif 2012-13. The experimental material comprised of 20 genotypes along with one check of brinjal and the experimental was laid out in randomized block design with three replications. Variability studies revealed that highly significant differences were recorded among the varieties for all characters. Correlation and path analysis revealed that fruit length, diameter, weight influenced the fruit yield in plant with high direct effect and significant positive correlation. Therefore, fruit length, diameter, weight are an important characters which may be included in selection criteria for improvement in fruit yield per plant.

Bioefficacy of insecticides against Leucinodes orbonalis on brinjal.

Studies on bioefficacy of insecticides against brinjal shoot and fruit borer, Leucinodes orbonalis Guenee on brinjal were carried out during 2007 and 2008. The results on bioefficacy of insecticides showed that in terms of shoot infestation, emamectin benzoate (0.002%), endosulfan (0.05%), novaluron (0.01%) and lambda-cyhalothrin (0.004%) were found superior. The total number of drooping shoots was minimum (4.17) in emamectin benzoate followed by endosulfan (6.83) and novaluron (7.00), as compared to spinosad (9.17), deltamethrin (11.67) and Bacillus thuringiensis (13.17). In terms of reduction in fruit infestation, emamectin benzoate (0.002%) was highly effective followed by endosulfan (0.05%), agrospray oil T (0.2%) and spinosad (0.0024%). However, cost benefit ratio was highest in agrospray oil T (0.2%) followed by lambda-cyhalothrin (0.004%), endosulfan (0.05%) and deltamethrin (0.0028%).