Differential host preference of two allopatric strains of Euschistus heros (Hemiptera: Pentatomidae)

The Neotropical brown stink bug, Euschistus heros (Fabricius) (Hemiptera: Pentatomidae), is a key pest of Brazil's soybeans and recently became an economic pest on cotton. Euchistus heros has two allopatric strains: one prevalent in the South (SS), another prevalent in the North (NS) of South America and, a hybridization zone in the central region of Brazil where both strains co-occur. Knowledge of host preference and viability of these two E. heros strains are essential to understanding the population dynamics and movement of E. heros into crop fields. Our aims were 1) verify the preference of the E. heros strains and reciprocal hybrids [♀Nx♂S (HNS) and ♀Sx♂N (HSN)] between soybean and cotton plants and, 2) evaluate the immature development performance of the E. heros strains and reciprocal hybrids on soybean and cotton. We assembled host choice experiments in two life stages (4^th instar and adult females) and evaluated the immature survival on soybean and cotton plants. Our results showed that the SS prefer soybean over cotton. NS and hybrids choose randomly between soybean and cotton. Pure SS and NS are not able to active adulthood on cotton, only on soybean. Hybrid strains can develop on cotton (however, lower than 1% of survival) and soybean plants. The host choice results indicate that the recurrent E. heros attacks on cotton crops may be related with the hybrid strain in the central region of Brazil.