Neem kernel as an antifeedant against the tobacco caterpillar (Spodoptera Litura F.)

Phytoparasitica - Laboratory tests showed that neem (Melia azadirachta L.) seed kernel suspension in water at 3% was effective as an antifeedant against all the five instars of the tobacco...     

Granular systemic insecticides for control of green peach aphid (Myzus persicae) and their effect on yield and quality of tobacco grown in riverside lankas

Abstract

Flue‐cured Virginia (f.c.v.) tobacco grown on deltaic islands or lankas in the Godavari river in Andhra Pradesh, India is subject to heavy infestations of green peach aphid, Myzus persicae Sulz. The relative efficacy of granular formulations of the systemic insecticides phorate, disulfoton, carbofuran, aldicarb and terbufos in controlling the aphid, and their effect on the yield and quality of lanka tobacco have been studied. Aldicarb granules at 1 g/plant and disulfoton at 2 g/plant were found to be the most effective in controlling the aphid, and also resulted in higher yields of green leaf, cured leaf and total bright leaf equivalent (an index of visual quality). Terbufos at 2 g/plant also gave good yields, but was slightly less effective in controlling aphid infestations. Carbofuran at 3 g/plant was the least effective. The chemical quality of f.c.v. tobacco was not affected by the application of granular insecticides to the soil.     

Efficacy of diflubenzuron and neem seed kernel suspension against the tobacco caterpillar,spodoptera litura,in tobacco nurseries

Nursery tests showed that aqueous sprays of a 25% diflubenzuron (DFB) W.P. at 0.007%, 0.009%, 0.011% and 0.013% a.i., a 2% neem seed kernel suspension (NSKS) in water and a combination of 1% NSKS plus 0.0035% DFB protected tobacco seedlings from tobacco caterpillar (Spodoptera litura [F.]) damage up to 9 days after spraying. Weekly treatments in a bulk nursery with 0.009% DFB and 2% NSKS commencing 4 weeks after germination and continued for 7 weeks, offered significant protection and significantly reducedS. litura larval population compared with an unprotected nursery.     

Goniophotometric study of reflectance of non-circular cross-section polyester monofilament and its yarn under various applied tensions

The relative intensity-angular distribution of surface reflectance of one kind of non-circular cross-section (NCCS), herein referred to as octagonal cross-section, polyester monofilament and its yarn was investigated. Using a goniophotometer (GP), both the horizontally and vertically mounted substrate geometries were used, with the fiber or yarn at various, but known, tensions. An angle of incidence of 45° with respect to the fiber axis was used for the horizontally mounted fiber. The results indicate that the (specular) maximum appears at the expected surface reflectance angle around 40°, with the fiber held straight under applied load. The maximum in the reflection profile for the vertically mounted fiber or yarn, under the same conditions, was around 85°. It was also found, as is to be expected, that the calculated luster of the octagonal cross-section fiber and its yarn, using a Gaussian fitting model, was affected significantly by the load applied for both the horizontal and vertical geometries of the substrate. Further, it was observed that the relative reflection intensity of vertically mounted single octagonal fiber/monofilament was higher than that of horizontally mounted one under the same value of applied tension, while it was the reverse for the yarn from these filaments. With increased tension, the shine values of both horizontally and vertically mounted single fiber increased while those of its corresponding yarn decreased. Further, for both the horizontally and vertically mounted fiber, the difference in shine values for the two cases of tension and no tension was large, whereas such differences were much smaller for the yarn.     

Effect of a neem seed kernel suspension onTelenomus remus,an egg parasite ofSpodoptera litura

Laboratory tests showed that a 2% neem (Azadirachta indica A. Juss) seed kernel suspension (NSKS) in water sprayed onSpodoptera litura (F.) eggs before or after parasitization did not adversely affect the emergence of the egg parasiteTelenomus remus Nixon. When sprayed on eggs before parasitization, the treatment did not repel the parasite. The treatment accelerated the development of the parasite but significantly reduced the longevity of its adult. When parasitized eggs were treated, NSKS significantly increased the adult parasite longevity. Thus, a schedule of NSKS sprays can be integrated withT. remus for the control of the tobacco caterpillar,S. litura, in tobacco nurseries.     

Prediction of heterosis for grain yield in rice using 'key' informative EST-SSR markers

This study was undertaken to assess the comparative potential of 25 Expressed Sequence Tag derived simple sequence repeats (EST-SSRs) and 25 genomic SSRs in the prediction of grain yield heterosis using a set of nine cytoplasmic male sterile (CMS) lines and 32 restorer lines of rice. EST-SSRs and genomic SSRs exhibited an average Polymorphism Information Content value of 0.37 and 0.45, respectively. The coefficient of marker polymorphism among parental lines with respect to a set of hypervariable EST and genomic SSRs was correlated with standard heterosis for grain yield of six public bred rice hybrids. EST-SSRs gave a better correlation (r = 0.75) as compared with genomic SSRs (r = 0.09). When 10 'key' informative EST-SSR markers which showed a higher positive correlation with grain yield heterosis were validated in a new set of 14 experimental hybrids, the markers exhibited a higher correlation (r = 0.79), indicating the predictive value of these EST-SSRs. We recommend these 10 'key' informative EST-SSR markers for analysis of genetic diversity of parental lines and prediction of heterosis in hybrid rice breeding programmes.     

Neem seed kernel suspension as an antifeedant forSpodoptera Litura in a planted flue-cured Virginia tobacco crop

Field experiments showed that a neem (Azadirachta indica A. Juss) seed kernel suspension (NSKS) at 0.5%, 0.75% or 1% concentration gave significant protection to the tobacco crop against the tobacco caterpillar (Spodoptera litura F.) up to 7 days after spraying. None of the treatments had any adverse effect on yield or chemical and physical quality characteristics of the flue-cured Virginia tobacco. The smoke quality assessment revealed that tobacco leaves sampled from 0.5%-NSKS-sprayed plots did not have any perceptible taint in the smoke and were acceptable by the trade. In an organoleptic evaluation of NSKS-treated tobacco samples, the testers preferred cigarettes made from tobacco of either untreated samples or those treated with 0.5% NSKS. Thus, the tobacco crop can be effectively and economically protected against S. litura damage by spraying the tobacco leaves with 0.5% NSKS.