P. D. KamalaJayanthi ¹, R. Rajanikanth ¹, Abraham Verghese ²

Affiliations
1 Department of Entomology and Nematology, Indian Institute of Horticultural Research, Hessaraghatta Lake PO, Bangalore 560 0 Karnataka, IN
2 National Bureau of Agriculturally Important Insects, P.B. No. 2491, H.A. Farm Post, Hebbal, Bangalore 560 024, Karnataka, IN

Abstract

The present study explains an efficient method for identifying the good foragers among the Cryptolaemus montrouzieri Mulsant populations for genetic studies where the trait accuracy is of utmost importance. Subjecting the adult C. montrouzieri beetles to pre-starvation was found to be an accurate method for identifying the good foragers over continuous feeding.

Keywords

Cryptolaemus montrouzieri, Predatory Coccinellid, Screening, Continuous Feeding, Pre-Starvation.

Full Text

   

P. D. Kamala Jayanthi ¹, P. Sangeetha ¹, Abraham Verghese ¹

Affiliations
1 Department of Entomology and Nematology, Indian Institute of Horticultural Research, Hessaraghatta Lake PO, Bangalore 560089, IN

Abstract

The relationship of food consumption during the grub stage with the subsequent adult stage of female Cryptolaemus montrouzieri (Coleoptera: Coccinellidae), and the impact of food consumption on its fecundity was studied. Food consumption of the adult female C. montrouzieri was found to be positively correlated with food consumption during the grub stage and the regression analysis explained 54% of the variability (y = 0.3418x + 1.3884; R² = 0.542). Further, fecundity was found to be linked to the adult female's food consumption with a highly significant positive correlation to consumption of previous 1st day (r = 0.83), 2nd day (r = 0.82), 3rd day (r = 0.81), 1st + 2nd day (r = 0.83), 2nd + 3rd day (r = 0.82) as well as to cumulative food consumption (r = 0.83). Linear and non-linear functions explained the relationship between amount of food consumed and numbers of eggs laid to the extent of 85% (y = 1.6075x + 46.8; R² = 0.8456) and 89% (y=15.198x^0.5681; R² = 0.8854), respectively. Thus, selection for high food consumption in the grub stage also selects indirectly C. montrouzieri adult females that lay copious quantities of eggs.

Keywords

Cryptolaemus montrouzieri, Feeding, Fecundity, Life Stages.

Full Text

   

Abraham Verghese ¹

Affiliations
1 Fruit Entomology Laboratory, Indian Institute of Horticultural Research, Hessaraghatta Lake P.O., Bangalore 560 089, IN

Abstract

Studies carried out in a guava ecosystem on three aphidophagous coccinellid predators showed that Cheilomenes sexmaculata (Fabricius), was spatially aggregated throughtout, while Pseudaspidimerus circumflexa (Motschulsky) and Scymnus castaneus (Sicard) had an initial random distribution which later tended to aggregation with increased mean density. However, aggregation did not seem to influence sample number with a nonsignificant correlation. Appropriate sampling plans were developed for all the three predators. At 25% precision level, the number of trees for sampling were 18, 32 and 48, respectively for the three species. A linear model was also developed to ardve at an optimum sample number for combined or individual predator estimation. As per the linear model, for example, a mean density of 2 predators/tree would require 26 trees. The sampling plans which are on sound ecological lines have relevance in biological control studies.

Keywords

Aggregation, Sampling, Cheilomenes sexmaculata, Pseudaspidimerus circumflexa, Scymnus castaneus, Guava.

Full Text

   

Enakshi Ghosh ¹, Chandish R. Ballal ², Abraham Verghese ³

Affiliations
1 Department of Biotechnology, Center for Post Graduate Studies, Jain University, Jayanagar, 9 Bengaluru – 560011, Karnataka, IN
2 ICAR- National Bureau of Agricultural Insect Resources, P. Bag No. 2491, H.A Farm post, Bellary Road, Bangalore – 24, IN
3 GPS Institute of Agricultural Management, Bengaluru - 560058, IN

Abstract

The effect of temperature on different Trichogramma spp. is an aspect to be understood for planning mass production strategies and further field releases. The key biological parameters of seven different spp./strains of trichogrammatids (viz. Trichogramma japonicum Ashmead, T. cordubensis Vargas and Carbello, T. achaeae Nagaraja and Nagarkatti, four strains of T. chilonis Ishii i.e. lab strain, Nilgiris strain, Kodaikanal strain and a strain acclimatized to constant 15°C) were investigated at five constant temperatures (16, 21, 26, 31 and 36±1°C with 60-70% RH and L: D-12:12). The different test temperatures had a significant impact on the biological parameters of the different species/strains. Based on longevity, parasitism and fecundity attributes, the best temperature to propagate these trichogrammatids was found to be 26°C. Considering the higher parasitism rates and the ability to parasitize and remain fecund at varied temperatures, T. chilonis Nilgiris strain proved to be the best. From the linear model of regression analysis, the upper temperature thresholds ranged from 35 to 46.37°C and the lower temperature thresholds were recorded to range between 9 and 12°C, with T. cordubensis appearing to be least temperature sensitive.

Keywords

Biology, Effect of Temperature, Trichogramma.

Full Text