Compatibility of Beauveria bassiana (Balsamo) vuillemin with Amblyseius cucumeris Oudemans (Acarina : Phytoseiidae) to control Frankliniella occidentalis Pergande (Thysanoptera : Thripidae) on cucumber plants
Rj. Jacobson et al., Compatibility of Beauveria bassiana (Balsamo) vuillemin with Amblyseius cucumeris Oudemans (Acarina : Phytoseiidae) to control Frankliniella occidentalis Pergande (Thysanoptera : Thripidae) on cucumber plants, BIO SCI TEC, 11(3), 2001, pp. 391-400
The effects of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vui
llemin on populations of the western flower thrips, Frankliniella occidenta
lis Pergande (Thysanoptera: Thripidae) feeding on cucumbers, and its compat
ibility with the predatory mite, Amblyseius cucumeris [Neoseiulus cucumeris
] Oudemans (Acarina. Phytoseiidae), were studied in laboratory and glasshou
se experiments. Two proprietary B. bassiana-based mycopesticides were used:
Naturalis-L (Troy Biosciences Inc., USA) and BotaniGard WP (Mycotech Corp.
, USA). Two high volume sprays of Naturalis-L, applied with a six day inter
val to glasshouse-grown cucumber crops, reduced numbers of immature F. occi
dentalis by 75% compared to an untreated control during the three weeks fol
lowing the first application. Glasshouse populations of F occidentalis were
also reduced by 65-87% with three consecutive high volume sprays or low vo
lume mist applications of Naturalis-L or BotaniGard WP, applied at six day
intervals. Prophylactic release of A. cucumeris in glasshouse-grown cucumbe
rs prevented population increases of F. occidentalis. Naturalis-L had no de
trimental effect on A. cucumeris when sprayed onto excised cucumber leaves
in a laboratory bioassay, or when sprayed onto glasshouse-grown cucumbers.
There was no evidence that control of F. occidentalis was impaired by appli
cation of Naturalis-L onto plants already treated with A. cucumeris. The st
udy suggests that a mycopesticide could be used as a second line of defence
to support preventative pest management with A. cucumeris. This strategy p
rovides a way forward for biological control in protected crops.