Importation an preliminary evaluation of the stem-boring moth, Buakea kaeuae as a potential biological control agent of invasive Guineagrass, Megathyrsus maximus

Authors: VACEK, ANN - University Of Texas Rio Grande Valley; Goolsby, John; CATALYUD, PAUL - African Insect Science For Food And Health (ICIPE); LE RU, BRUNO - African Insect Science For Food And Health (ICIPE); MUSYOKA, BOAZ - African Insect Science For Food And Health (ICIPE); KARIYAT, RUPESH - University Of Texas Rio Grande Valley

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/3/2020
Publication Date: 3/25/2021
Citation: Vacek, A.T., Goolsby, J., Catalyud, P.A., Le Ru, B.P., Musyoka, B.K., Kariyat, R.R. 2021. Importation an preliminary evaluation of the stem-boring moth, Buakea kaeuae as a potential biological control agent of invasive Guineagrass, Megathyrsus maximus. Southwestern Entomologist. 46. https://doi.org/10.3958/059.046.0125.
DOI: https://doi.org/10.3958/059.046.0125

Interpretive Summary: Guineagrass, Megathyrsus maximus (=Panicum maximum), is an African grass that is in many parts of the world, including South Texas. Although it has some value as a pasture grass, it also causes many problems including: enhances the survival of cattle fever ticks, Rhipicephalus microplus and Rhipicephalus annulatus along the U.S.-Mexico transboundary region; invades subtropical perennial crops such as sugarcane and citrus, reduces populations of granivourous birds such as quail; and alters fire regimes in South Texas rangelands. South Texas rangelands have been invaded by a unique small form of Guineagrass that is genetically distinct from other Guineagrass populations worldwide. We evaluated a stem-boring moth, Buakea kaeuae, from Kenya as a biological control agent for Guineagrass, but neither larvae nor adults developed or reproduced on Texas Guineagrass.

Technical Abstract: Guineagrass, Megathrysus maximus (=Panicum maximum), is an African grass that is invasive in Florida, Hawaii, southern Texas, and northeastern Mexico. Guineagrass outcompetes many native grasses and forbs and causes habitat degradation, increased fire risk, weed problems in agricultural fields, and increased populations of cattle fever ticks, Rhipicephalus microplus and Rhipicephalus annulatus. Buakea kaeuae, a stem-boring African moth found only on M. maximus, was imported from Kenya and evaluated for its ability to feed and develop on Guineagrass naturalized in southern Texas. Neither larvae nor adults developed or reproduced on Texas Guineagrass. This most likely indicates that TX Guineagrass is genetically or phytochemically different from small Guineagrass in Machakos, Kenya.