Oviposition preferences of Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae) on four Brassica and two Sinapis species (Brassicaceae) in field cages

The oviposition preferences of Lygus lineolaris (Palisot de Beauvois) were studied on Brassica carinata A. Braun, Brassica juncea (L.) Czern, Brassica napus L., Brassica rapa L., Sinapis alba L. (high glucosinolates), Sinapis alba L. (low glucosinolates), and Sinapis arvensis L. in a choice test during a 14-day period in field cages. Host-plant discrimination occurred on at least two levels. The first level occurred at the generic level; ovipositing females first selected species of Sinapis on which to lay eggs and later laid on species of Brassica. On species of Sinapis, 80% or more of the total number of eggs were laid during days 1-6, whereas only 35-58% were laid during this period on species of Brassica. The second level occurred at the species level in both Brassica and Sinapis. In Brassica, significantly more eggs were laid on B. carinata and B. napus than on B. juncea; in Sinapis, significantly more eggs were laid on S. alba (high glucosinolates) than on S. arvensis. The numbers of eggs did not differ significantly among B. carinata, B. napus, and S. alba (high glucosinolates). The numbers of eggs on B. rapa and S. alba (low glucosinolate) were not significantly different from those on the other five Brassica and Sinapis hosts tested. Host-plant selection seemed to be unaffected by glucosinolate levels in the seed of S. alba.