Damage to wheat seeds caused by a plant bug, Lygus lineolaris L.

Abstract

Wise, I. L., Tucker, J. R. and Lamb, R. J. 2000. Damage to wheat seeds caused by a plant bug, Lygus lineolaris L. Can. J. Plant Sci. 80: 459-461. Adults of the plant bug, Lygus lineolaris L., cause bleached areas on wheat seeds when they feed. Affected areas are irregular in shape and extend into the endosperm, with necrotic lesions where the insects' mouthparts puncture the surface. This seed damage occurs in commercial wheat from many parts of western Canada.Key words: Starchy seeds, non-vitreous kernels, durum wheat, seed damage Wise, I. L., Tucker, J. R. et Lamb, R. J. 2000. Endommagements des grains de blé par la punaise terne Lygus lineolaris L. Can. J. Plant Sci. 80: 459-461. Les déprédations de l'adulte de la punaise terne Lygus lineolaris causent l'apparition de plages décolorées à la surface des grains de blé. Les plages, de forme irrégulière s'étendent à l'endosperme et présentent des lésions nécro-tiques aux points où les pieces buccales de l'insecte perforent la surface. Ce type d'endommagement s'observe dans les cultures commerciales du blé dans plusieurs régions de l'ouest canadien. Mots clés:Grain amylacé (mitadiné), grain non vitreux, blé dur, endommagement du grain Plant bugs, Lygus spp. (Heteroptera: Miridae), are pests of many crops in western Canada, reducing yield of canola (Wise and Lamb 1998) and seed alfalfa (Craig 1983) by damaging developing seeds (Butts and Lamb 1990). These plant bugs or related true bugs are suspected of causing damage to seeds of Canadian wheat, although the causative agent of the damage has not been confirmed. In Europe, Lygus rugulipennis Poppius feeds on wheat and affects seed viability (Varis 1991). In New Zealand, the wheat bug, Nysius huttoni White, damages wheat seeds and its salivary proteinases affect the baking quality of wheat flour (Every et al. 1998). In North America the tarnished plant bug, Lygus lineolaris (Palisot de Beauvoir), is ubiquitous and feeds on at least 19 species of grasses, including wheat plants (Young 1986). The objectives of this study were to confirm that adults of L. lineolaris feed on the seeds of wheat, determine if their feeding causes characteristic damage to seeds, and assess whether such damage is common in wheat from western Canada. The study was undertaken when many plant bugs were found and appeared to be feeding in research plots of wheat.Adult L. lineolaris were collected in September 1998 with a sweep net from alfalfa in Winnipeg, Manitoba. Groups of 1-3 wheat heads at the late milk to early dough stages were exposed to 10 or 20 adults in 15 clear plastic cages (110 mm in diameter and 300 mm in height), giving infestation levels of 3.3, 5, and 10 adults per head. Groups of heads from 10 additional plants were caged without insects as controls. Greenhouse-grown plants of the cultivars Glenlea and Wildcat were selected because they were free of pests, and had numerous tillers at the desired growth stage. As additional controls, the 25 plants were left with an average of two wheat heads outside the cages. The plants were m...

Seasonal occurrence and within-field distribution of Lygus lineolaris on buckwheat in Manitoba

“…1A, 1B). Adult lygus bugs can fly great distances in search of food (Stewart and Gaylor 1994) and are known to migrate to and feed on late-maturing spring wheat in late summer (Wise et al 2000).…”