Mb. Thomas et al., BIOLOGICAL-CONTROL OF LOCUSTS AND GRASSHOPPERS USING A FUNGAL PATHOGEN - THE IMPORTANCE OF SECONDARY CYCLING, Proceedings - Royal Society. Biological Sciences, 259(1356), 1995, pp. 265-270
Persistent chemical pesticides can provide an effective means of contr
ol against locusts and grasshoppers due to prolonged activity of the s
pray residue. However, use of these pesticides is now prohibited, and
nonpersistent chemical alternatives are substantially less successful.
Here we show why it is expected that biological pesticides based on t
he fungal pathogen Metarhizium flavoviride will be highly effective in
the control of both locust and grasshopper. We demonstrate, using nov
el population dynamic models containing measured estimates of horizont
al transmission coefficients, that secondary cycling of the pathogen a
fter a single spray application provides a biological substitute for c
hemical persistence. This has significant consequences for the economi
cs of biopesticide use in pest control. Furthermore, by identifying th
at secondary cycling acts in a density-dependent manner, this study al
so highlights fundamental differences between conventional pesticides
and biopesticides and how they might be used.