Search

High percentage of Homalotylus turkmenicus Myartseva (Hymenoptera: Encyrtidae) parasitizing Hyperaspis maindroni Sicard (Coleoptera: Coccinellidae) predating on the colonies of the Cassava Mealybug (CMB) Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae) is observed in southern India. In the present study, cautionary note on the presence of H. turkmenicus in the food web of insects associated with the CMB and brief diagnosis of the parasitoid is presented for quick identification. The parasitism of Hy. maindroni grubs by H. turkmenicus ranged from 65.67 to 80.95 per cent. However, no primary parasitoid of the cassava mealybug was observed so far.

High percentage of Homalotylus turkmenicus Myartseva (Hymenoptera: Encyrtidae) parasitizing Hyperaspis maindroni Sicard (Coleoptera: Coccinellidae) predating on the colonies of the Cassava Mealybug (CMB) Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae) is observed in southern India. In the present study, cautionary note on the presence of H. turkmenicus in the food web of insects associated with the CMB and brief diagnosis of the parasitoid is presented for quick identification. The parasitism of Hy. maindroni grubs by H. turkmenicus ranged from 65.67 to 80.95 per cent. However, no primary parasitoid of the cassava mealybug was observed so far.

Studies to identify effective kairomones, their optimum doses and appropriate application techniques with a view to increase the parasitizing efficiency of T. chilonis were conducted during 2005-06 in the laboratory. Fresh hexane extract of Corcyra cephalonica (1%)+hexacosane (0.3%) and C. cephalonica scale extract (1%)+nonacosane (0.3%) were the most attractive and recorded the highest egg parasitization (77.25% in both) when applied in impregnated rubber septa. The second effective kairomone was C. cephalonica scale extract (1%)+pentacosane (0.3%). Kairomone impregnated septa as dispensers proved better over paper strips. No significant difference in parasitizing efficiency was recorded between ochre and orange septa kairomone dispensers.

Hexane wash of gallery and body of Opisina arenosella Walker elicited positive response from the parasitoids namely Goniozus nephantidis (Muesebeck), Brachymeria nephantidis Gahan and Elasmus nephantidis Rohwer, in terms of more number of parasitoids entering the kairomone arm than hexane arm in 'Y' tube olfactometer. Although, numerically, the gallery wash elicited higher response than larval body wash of the host O. arenosella to G. nephantidis, statistically, the treatments were on par. Chemical analysis of kairomonal substances using GCMS revealed the presence of 13-tetradecenal and myristic acid in the gallery wash, in addition to dodecane, pentadecane, hexadecane, heptadecane, eicosane and tricosane. Larval wash showed terpenoids like alpha-terpinene and alpha humulene.

No Abstract.

Chrysopids being efficient predators are used against pests of several important crops (Canard et al., 1984). Techniques for mass rearing of these chrysopids were developed by several workers (Morrison, 1977; Krishnamoorthy and Nagarkatti, 1981; Patel et al., 1987). Elsewhere in the world, detailed studies were conducted on the long term storage of the eggs of chrysopids (Tauber et al., 1993). However, reports on the storage of the eggs of chrysopids are lacking in India. An attempt was made to find out the optimum temperature and age of the eggs of Chrysoperla carnea (Stephens) for short term storage and the results are communicated in this short paper.

The eggs of Tenodera aridifolia sinensis (Saussure) were parasitised by Podagrion sp. in Nagaland. The per cent oothecae parasitised was 28 and 40.6 during 1987 and 1988, respectively.

Laboratory and field cage experiments were conducted to select the best kairomone as an ovipositional attractant for Chrysoperla carnea (Stephens). Acid hydrolysed L-tryptophan (15 days after storage) was found to be highly attractive to the males and females of C. carnea in no choice method, using wind tunnel method and in multiple choice method using the kairomone treated filter paper. Pure commercial honey, 25 per cent and 50 per cent honey solutions were attractive in no choice method but not in the multiple choice method. Highest number of eggs were laid on the filter paper sprayed with 15 days old L-tryptophan in laboratory study. However, in the field cage studies, only 3 day old L-tryptophan recorded highest oviposition on cotton plants treated with the kairomones, probably the breakdown product of L-tryptophan is not effective in long range if stored beyond 7 and 15 days. Possibility of using L-tryptophan in the field is discussed.

Behavioural and electrophysiologieal responses of adult Chrysoperla carnea (Stephnes) were studied in laboratory conditions (27±2°C and RH 70%). The females of C. Carnea in thc ovipositional period were exposed to acid hydrolysed L-tryptophan using hydrochloric acid, oxidizcd L-tryptophan using hydrogen peroxide and quick amino acid oxidizers. The response of C. Carnea females to both hydrolysed and oxidized L-tryptophan was greater at higher concentratiun (0,66%) than lower concentration (0.33%). The orientational response studies have shown that more Humber of adults was attracted to the acid hydrolyzed L-tryptophan than oxidized L-tryptophan. Ovipositional studics indicated that acid hydrolyzed L-tryptophann recorded higher oviposition, followed by oxidized L-tryptophan using quick oxidizers. The role of the quick oxidizers in fast breakdown of L-tryptophan and subsequcnt ovipositional attraction was studied by exposing C. Carnea to 2 or 3-day-old acid hydrolyzed and oxidized L-tryptophan. Higher oviposition was recorded in the 3-day-old formulation compared to 2-day-old acid hydrolyzed and oxidized L-tryptophan. The ultimate breakdown product of L-tryptophan, which was responsible for the attraction of L-tryptophan, was considered to be indole acctaldehyde. The attraction of C. Carnea to indole acetaldehyde was also studied at 10. 20 mM. There was Significantly more oviposition on the fiIter paper discs treated with IOmM indole acetaldehyde. Thc prospects of lIsing these products as attractants are discussed.

No Abstract.

Laboratory and field cage experiments were conducted to select the best kairomone as an ovipositional attractant for Chrysoperla carnea (Stephens). Acid hydrolysed L-tryptophan (15 days after storage) was found to be highly attractive to the males and females of C. carnea in no choice method, using wind tunnel method and in multiple choice method using the kairomone treated filter paper. Pure commercial honey, 25 per cent and 50 per cent honey solutions were attractive in no choice method but not in the multiple choice method. Highest number of eggs were laid on the filter paper sprayed with 15 days old L-tryptophan in laboratory study. However, in the field cage studies, only 3 day old L-tryptophan recorded highest oviposition on cotton plants treated with the kairomones, probably the breakdown product of L-tryptophan is not effective in long range if stored beyond 7 and 15 days. Possibility of using L-tryptophan in the field is discussed.

Chrysopids being efficient predators are used against pests of several important crops (Canard et al., 1984). Techniques for mass rearing of these chrysopids were developed by several workers (Morrison, 1977; Krishnamoorthy and Nagarkatti, 1981; Patel et al., 1987). Elsewhere in the world, detailed studies were conducted on the long term storage of the eggs of chrysopids (Tauber et al., 1993). However, reports on the storage of the eggs of chrysopids are lacking in India. An attempt was made to find out the optimum temperature and age of the eggs of Chrysoperla carnea (Stephens) for short term storage and the results are communicated in this short paper.