Candidate Attractants for Bactrocera invadens (Diptera: Tephritidae) Male Flies from Gynandropsis gynandra (Capparidaceae)

Abstract

These investigations aimed at evaluating the attractiveness of Gynandropsis gynandra a plant that attracted male Bactrocera invadens, which is an invasive pest known to cause devastating losses in mangoes, citrus, guava and banana among other fruits. B. invadens male flies were attracted to G. gynandra beginning from 0630 to 1230 hrs in the field.  The highest mean number of flies attracted were 65.26 ± 1.06/plant/day, showing a strong positive correlation during the day (r² = 0.9423). Using GC-EAD and GC-MS two compounds namely, 4-methyl-3-penten-2-one, and 4-hydroxy-4-methyl-2-pentanone were identified to elicit antennae response of the male B. invadens. These two compounds were identified from both G. gynandra and male B. invadens gut extracts of field collected flies. However only 4-hydroxy-4-methyl-2-pentanone was identified from gut extract of laboratory reared B. invadens.  Results from this study has provided an insight into the interactions between a non-host plant and an invasive pest, and opened up the prospects for further investigation on the possibility of future use of 4-hydroxy-4-methyl-2-pentanone and 4-methyl-3-penten-2-one in control strategies aimed at B. invadens.

Key words: Bactrocera invadens, parapheromones, olfactometer, GC-EAD