Biological control of rice stink bugs in Brazil: An overview

Stink bugs are among the main insect pests of rice production in Brazil. Two species –

the Stalk Stink Bug Tibraca limbativentris and the Grain Stink Bug Oebalus pugnax

(Hemiptera: Pentatomidae) are found throughout the country. Both are native from

Central and South America and have some natural enemies stablished in rice fields, but

not enough to keep them under control. The parasitoids Telenomus podisi and

Trissolcus basalis (Hymenopter: Scelionidae) were introduced in an IPM program for

soybean pests but are vastly found and effective for the rice bugs too. Ranges of 75 –

89% of penatomid eggs were parasitized by these wasps in commercial rice

fields. In the same way, entomopathogenic fungi as Metarhizium anisopliae and

Beauveria bassiana are found to control 50 – 60% of the T.limbativentris population

during the growing season, and they can also be used on the offseason, in hibernation

sites. Several commercial biopesticides with these entomopathogenic fungi are

available. Even though the willing for biological control is increasing all over the

county, there are still many issues for this technology as the combination with

chemical control as well as the availability and logistic for the parasitoids. Fungicides

sprayed for rice blast Magnoporthe oryza are lethal for the entomopathogenic fungi,

and most of the insecticides are not selective for the parasitoids. Biological control is

growing very slowly and can be increased by some new tools as some strains of

Bacillus sp. and even some elicitors to increase the attraction and efficiency of the egg

parasitoids.