Effects of Beauveria bassiana (Balsamo) Vullemin on food consumption and mobility of the orchid lema, Lema pectoralis Baly (Coleoptera: Chrysomellidae)

Issue Date

10-2004

Abstract

Under laboratory conditions, Bb 1 isolate of Beauveria bassiana (Balsamo) Vullemin was evaluated for its effects on Vanda flower consumption and mobility of a major insect pest (Lema pectoralis Baly) of orchids. The isolate positively caused cessation of feeding activity in orchid lemas when 10 ul of 1.62 x108 spores per ml (suspended in 0.01% Triton X-100) was applied on each insect. The CFT50 (ceased Feeding Time) or time when 50% of treated insects completely ceased feeding were 4.723 days and 5.151 days for males and females, respectively. the LT50 (Lethal Time) or time taken to kill 50% of treated insects was 5.793 days for males and 5.853 days for females. CFT50 values were lower than the LT50 values, indicating that cessation of feeding of treated insects occurred earlier than their death. Reduction in food consumption of treated insects compared to the control was significant (P<0.001). There was also significant (P<0.001) loss in weight of treated insects. Sluggishness and incapability to crawl or fly were also observed in treated insects starting at day 3 after treatment in another set-up. Amount of food consumed by females, regardless of treatment, was generally greater than that by males, indicating that the former are more damaging to orchid. The control males tended to gain more weight than the control females, but treated males lost more weight than treated females. Infection of B. bassiana may therefore be faster in males than in females.

Source or Periodical Title

Philippine Entomologist

ISSN

0048-3753

Volume

18

Issue

2

Page

171-172

Document Type

Article

Frequency

semi-annually

Language

English

En – AGROVOC descriptors

BEAUVERIA BASSIANA; COLEOPTERA; CHRYSOMELLIDAE; FOOD CONSUMPTION; PLANT PESTS; PEST CONTROL

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