Augmentative on-farm delivery methods for the parasitoid Habrobracon hebetor Say (Hymenoptera: Braconidae) to control the millet head miner Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae) in Burkina Faso and Niger

Abstract

Augmentative on-farm delivery methods for the parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) to control the millet head miner (MHM) Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae) were investigated in Burkina Faso from 2011 to 2012 and in Niger in 2012. Our findings indicate that 7 cm 9 10 cm jute bags containing 50 g of millet grains, 30 g of millet flour, 25 Corcyra cephalonica larvae and two mated H. hebetor females are the most effective option for on-farm delivery of the parasitoid. The parasitoid progeny started emerging from the bags eight days after confinement and 57-71 parasitoid adults emerged from each bag. Using the methods we developed, over 90 % parasitism of MHM larvae was achieved in millet farms. The implications of these findings for a large extension of MHM biocontrol program are discussed.

Timing of releases of the parasitoid Habrobracon hebetor and numbers needed in augmentative biological control against the millet head miner Heliocheilus albipunctella

“…Habrobracon hebetor larvae were reared on the rice moth, Corcyra cephalonica Stainton (Lepidoptera: Pyralidae) and maintained in the laboratory throughout the study period at fluctuating room temperatures (mean = 26 ± 2°C) at the entomology Laboratory of INRAN (Institut National de la Recherche Agronomique du Niger) in Maradi. Rice moths were reared on a mixture of pearl millet grain and flour in wooden cages (20 9 20 9 13 cm), and the parasitoids were reared on third and fourth instar C. cephalonica larvae using the technique described by Ba et al (2014).…”

“…The selected twelve villages were divided into four groups of three and assigned to one of the following treatments: (1) three villages each were supplied with 15 parasitoid bags at the pearl millet panicle emergence stage, (2) three villages each with 15 parasitoid bags at the pearl millet male flowering stage, (3) three villages each with 15 parasitoid bags at the pearl millet grain filling stage, and (4) three ''control villages'' did not receive any parasitoids. All three villages, in the same treatment, were separated by at least 5 km and all groups of villages of different treatments were at least 15 km away from each other (Ba et al 2014). The parasitoids were released using jute bags of 15 cm 9 25 cm containing 200 g of pearl millet grains, 100 g of pearl millet flour, 25 C. cephalonica larvae (a mixture of third and fourth instars) and two mated H. hebetor females.…”

“…The parasitoids were released using jute bags of 15 cm 9 25 cm containing 200 g of pearl millet grains, 100 g of pearl millet flour, 25 C. cephalonica larvae (a mixture of third and fourth instars) and two mated H. hebetor females. In each release village, the parasitoid bags were evenly distributed within five pearl millet fields (three bags per farmer's field) using the method described by Ba et al (2014). The jute bags were suspended to the ceiling of traditional straw granaries located in farmers fields and emerging parasitoids were able to escape through the jute mesh and straw granaries and disperse to parasitize MHM larvae in millet fields (Ba et al 2013(Ba et al , 2014.…”

“…Biological control has emerged as the most attractive solution for controlling the MHM and the gregarious parasitoid Habrobracon (= Bracon) hebetor Say (Hymenoptera: Braconidae) is considered a natural enemy with great biocontrol potential (Gahukar et al 1986;Bhatnagar 1987). Recently, augmentative releases of H. hebetor have been successful against the MHM in Niger (Payne et al 2011;Ba et al 2013Ba et al , 2014Baoua et al 2014Baoua et al , 2018. This has led to parasitism of up to 80% of the MHM larvae (Ba et al 2013(Ba et al , 2014, resulting in 34% increase in grain yield .…”

“…Recently, augmentative releases of H. hebetor have been successful against the MHM in Niger (Payne et al 2011;Ba et al 2013Ba et al , 2014Baoua et al 2014Baoua et al , 2018. This has led to parasitism of up to 80% of the MHM larvae (Ba et al 2013(Ba et al , 2014, resulting in 34% increase in grain yield .…”