LIFE HISTORY TRAITS AND MANAGEMENT OF LITCHI FRUIT BORER, CONOPOMORPHA SINENSIS BRADLEY (LEPIDOPTERA: GRACILLARIIDAE)

Abstract

Litchi fruit borer (Conopomorpha sinensis Bradley) is an important and destructive pest which affects the litchi fruit production causing significant economic losses. An investigation was carried out to study the developmental time, survival, reproductive biology on three litchi varieties and comparative efficacies of synthetic and botanical insecticides against C. sinensis under the laboratory conditions (25 ± 2°C, 70-80% RH) of department of Entomology, HSTU, Dinajpur, Bangladesh during April to July, 2016. Among the tested varieties the longest adult developmental period was observed on madraji (25.10 days) and bombai (24.80 days) in male and female, respectively. In contrast, it was shortest in bedana (22.10 and 20.70 days) variety on both female and male sexes. The longest adult longevity period were observed on madraji (12.70 days) and bedana (11.40 days) both for female and male, respectively. On the contrary, it was shortest on bombai (10.60 days) variety in both sexes. Life time fecundity was the highest on madraji (29.40) and the lowest in bedana (18.40) variety. Life table parameters were analyzed and the longest mean generation time (T) was found in madraji (37.65) and the lowest in bombai (35.55) variety. The net reproductive rate (Ro) (16.81), the intrinsic rate of natural increase (rm) (0.08), finite rate of increase (λ) (1.08) were the highest when reared in bombai litchi variety. A comparative study was also made for studying the efficacy of some botanicals and synthetic insecticides against litchi fruit borer larvae. Mortality percentages were directly proportional to the different concentration level and hours after treatments. Results showed that significantly different average mortality was found among the treatments and the highest average mortality caused by Gain 20 SL while the lowest mortality in control treatments. Efficacies of botanicals were also showed good results. The lowest LD50 value of botanical indicated that their highly effectiveness against litchi fruit borer. Based on these results, both the synthetic as well as botanical product especially chilli extract was performed well against the larvae of Conopomorpha sinensis.