K. I. Singh ¹, C. H. Singh ¹, M. P. Singh ¹, M. K. Gupta ¹

Affiliations
1 Department of Entomology, College of Agriculture, Central Agricultural University, Imphal 795004, Manipur, IN

Abstract

The predation efficiency of five species of coccinellids, namely, Coelophora biplagiata (Swartz), Coccinella transversalis F., Menochilus sexmaculatus (F.), Cryptolaemus montrouzieri Mulsant, and Chilocorus nigrita (F.), against cowpea aphid, Aphis craccivora Koch, was evaluated in the laboratory. Maximum consumption of A. craccivora (65.20 ± 0.59 to 214.60 ± 2.60) was observed in C. biplagiata released under various predator densities, whereas C. montrouzieri consumed the minimum numbers (19.40 ± 0.36 to 84.60 ± 0.73). C. biplagiata was closely followed by M. sexmaculatus and C. transversalis. It was also observed that C. biplagiata, M. sexmaculata and C. transversalis exhibited higher predation efficiency with a mean aphid consumption of 43.60 ± 0.46 to 485.80 ± 5.18, 41.20 ± 0.33 to 377.00 ± 3.35 and 40.60 ± 0.96 to 370.00 ± 3.74, respectively, under different prey densities of 45 to 720. When C. biplagiata was released, significantly lowest aphid population (23.06) was recorded, followed by M. sexmaculatus (35.26), C. transversalis (43.00) and C. nigrita (49.13) as against unreleased control (191.86). The highest aphid population (54.26) was recorded in the treatment where C. montrouzieri released.

Keywords

Aphis craccivora, Cowpea, Feeding Efficiency and Predaceous Coccinellids.

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Roshna Gazmer ¹, M. K. Gupta ¹, M. D. Singh ¹

Affiliations
1 College of Agriculture, Central Agricultural University, Imphal-795004, IN

Abstract

The biological parameters of Diaeretiella rapae and influence of the host age on the life cycle of the D. rapae. The fecundity of Diaeretiella rapae was 120-140 eggs per female. Eggs were transparent white but appeared light brownish under high magnification. Average incubation period was 1.90 days. Larvae of D. rapae underwent four moults. The first instar larva was transparent white, mandibulate, caudate and measured 0.57 mm in length and 0.14 mm in width and was active. The second instar larvae were creamy white and curved slightly, lacked mandibles, salivary gland and were hymenopteriform. They measured 0.77 mm in length and 0.19 mm in width. Third instar larvae were light yellow in colour, hymenopteriform and measured 1.22 mm in length and 0.43 mm in width. Fourth instar larvae measured 2.76 mm in length and 0.87 mm in width. The average total larval duration of D. rapae was 7.50 days. When the aphid host died, its body changed to hardened exoskeleton called mummy. Pupa measured 2.0 mm in length and 0.80 mm in width with average pupal duration was 5.60 days. Under laboratory condition, egg to adult development of D. rapae ranged from 13.75 to 16.00 days with an average of 15.0 days. The adult female parasitoid was bigger than male. Adult female measured 2.13 mm in length while male 1.78 mm in length. Longevity of adult was 6.4 days when 10% honey solution was provided and 4.4 days without honey solution. The life cycle parameters of parasitoid varied with the age of host insect. On 48 hrs old nymph of B. brassicae, the total duration required to form mummy was 13.6 days, in comparison to 14.6 days in case of 72 hrs old nymph and 11.5 days in case of 96 hours old nymphs. Total life cycle duration of the parasitoid was completed in 19.3 days, 20.1 days and 17.2 days when reared on 48 hrs, 72 hrs, and 96 hrs old nymph of B. brassicae respectively which indicated that the days required to form mummy, pupal period and duration from egg to adult emergence was comparatively shorter when D. rapae was reared on 96 hours old B. brassicae nymphs.

Keywords

Diaeretiella rapae, Brevicoryne brassicae, Fecundity, Biology and Life Cycle.

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A. K. Sarma ¹, M. K. Gupta ¹

Affiliations
1 College of Horticulture and Forestry, Central Agricultural University, Pasighat, IN

Abstract

An attempt was made to study the effectiveness of some traditional and non-traditional protection measures on the recovery of eri silkworm parasitized by uzi fly, Exorista sorbillans (Wiedemann). Maximum recovery was obtained in bamboo-sieve (71,15%), followed by uzinet (60.51%), bleaching powder (2%) solution (3S.41%) and neem leaf extract (33.83%), as against untreated control (14.79%). Physical barriers may be recommended for higher recovery of uzi-infested eri silkworms.

Keywords

Eri Silkworm, Exorista sorbillans, Recovery, Uzi Fly.

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D. Dey ¹, M. K. Gupta ¹, N. Karam ²

Affiliations
1 Department of Entomology, College of Agriculture, Central Agricultural University, Imphal-795004, IN
2 Directorate of Research, Central Agricultural University, Imphal-795004, IN

Abstract

Galerucella placida Baly is a small leaf beetle belonging to the family Chrysomelidae. which feeds on aquatic weed Polygonum hydropiper Linn. The insect was reported from various regions of India during 1910-1936. Investigation on some biological parameters of G. placida and feeding of the P. hydropiper by G. placida was conducted in laboratory. The results indicated the fecundity of G. placida was 710-1210 eggs per female. Eggs were markedly bright yellow, pyriform basally rounded and oval at tip. It measured 0.67 mm in length and 0.46 mm in width. Average incubation period was 3.80 days. Larvae of G. placida underwent three moults. The first instar larva was yellow in colour and measured 1.26 mm in length and 0.40 mm in width. The second instar was yellowish in colour but after an hour of feeding, the colour of the grub changes to blackish brown from yellow. It measured 2.64 mm in length and 0.77 mm in width. The third instar measured 5.59 mm in length and 1.96 mm in width. The average total larval duration of G. placida was 13.30 days. The fully developed pupa looked black in colour and measured 4.58 mm in length and 2.37 mm in width. Adult 4.50 days. The adult female was bigger than male. The adult male measured 5.60 mm in length and 2.35 mm in width and adult female measured 6.25 mm in length and 2.50 mm in width. Longevity of adult male was 35.40 days and while female was 40.40 days. Total life cycle duration of G. placida was completed in 21.60 days from egg to adult emergence. The damage was caused by both adult as well as grubs. At high population densities of adults and grubs, complete defoliation was seen. The average leaf area scrapped by larva and adult was 511.61 sq. cm and 866.35 sq. cm respectively.

Keywords

Galerucella placida, Polygonum hydropiper, Biology, Feeding.

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