TY - JOUR

T1 - Efficacy of crop cover netting against cabbage pests and their natural enemies and relevance of oilseed rape

AU - Ludwig, Martin

AU - Meyhöfer, Rainer

N1 - Funding Information: We thank gardeners and owners of the 11 horticultural farms for taking place in this study. We further thank Robert Lessing, Timo Michel and Jan-Uwe Niemann for help with fieldwork, Hella Schlinkert for help with fieldwork, statistics and proof reading, Gesa Elsner for digitisation of oilseed rape fields and Hans-Michael Poehling for valuable comments on an earlier version of this manuscript. This research is part of the “BMBF-AgroClustEr: WeGa—Kompetenznetz Gartenbau” and is funded by the “Bundesministerium für Bildung und Forschung” with the Grant Number 0315542A.

PY - 2016/12

Y1 - 2016/12

N2 - Crop cover nets are used in vegetables to reduce damage by pests. Recently, nets with 0.8 mm mesh size were recommended to protect Brassica vegetables from whiteflies, but farmers doubted their efficacy. We compared the impact of different mesh sizes on the abundance of insect pests and their antagonists on Brussels sprout in a field study and considered also important resource habitats, i.e. oilseed rape, in the surroundings. Cabbage whitefly was the most abundant pest followed by peach-potato aphid, cabbage aphid and diamondback moth. Aphid parasitism reached 48 % while syrphid larvae and spiders were the most abundant predatory taxa. The cabbage whitefly was less abundant under 0.8 mm nets in June and August compared to 7 mm nets, while no effect was observed in October. In general cabbage aphid, diamondback moth, syrphids and aphid parasitism were not affected by nets, but peach-potato aphid density increased under 7 mm nets late in the season. In contrast, spiders were less abundant under 0.8 mm than under 7 mm nets. Moreover, only the cabbage whitefly was positively affected by oilseed rape growing. In summary, 0.8 mm nets may be beneficial to reduce colonisation by cabbage whiteflies, especially in early summer and in landscapes with high colonisation pressure. Nets with wider mesh size may be appropriate in landscapes with low colonisation pressure by cabbage whiteflies since 0.8 mm mesh size had the disadvantages to support the peach-potato aphid and hinder colonisation by spiders.

AB - Crop cover nets are used in vegetables to reduce damage by pests. Recently, nets with 0.8 mm mesh size were recommended to protect Brassica vegetables from whiteflies, but farmers doubted their efficacy. We compared the impact of different mesh sizes on the abundance of insect pests and their antagonists on Brussels sprout in a field study and considered also important resource habitats, i.e. oilseed rape, in the surroundings. Cabbage whitefly was the most abundant pest followed by peach-potato aphid, cabbage aphid and diamondback moth. Aphid parasitism reached 48 % while syrphid larvae and spiders were the most abundant predatory taxa. The cabbage whitefly was less abundant under 0.8 mm nets in June and August compared to 7 mm nets, while no effect was observed in October. In general cabbage aphid, diamondback moth, syrphids and aphid parasitism were not affected by nets, but peach-potato aphid density increased under 7 mm nets late in the season. In contrast, spiders were less abundant under 0.8 mm than under 7 mm nets. Moreover, only the cabbage whitefly was positively affected by oilseed rape growing. In summary, 0.8 mm nets may be beneficial to reduce colonisation by cabbage whiteflies, especially in early summer and in landscapes with high colonisation pressure. Nets with wider mesh size may be appropriate in landscapes with low colonisation pressure by cabbage whiteflies since 0.8 mm mesh size had the disadvantages to support the peach-potato aphid and hinder colonisation by spiders.

KW - Aleyrodes proletella

KW - Brevicoryne brassicae

KW - Hoverfly

KW - Myzus persicae

KW - Net mesh size

KW - Plutella xylostella

UR - http://www.scopus.com/inward/record.url?scp=84991773785&partnerID=8YFLogxK

U2 - 10.1007/s41348-016-0038-8

DO - 10.1007/s41348-016-0038-8

M3 - Article

AN - SCOPUS:84991773785

VL - 123

SP - 331

EP - 338

JO - Journal of Plant Diseases and Protection

JF - Journal of Plant Diseases and Protection

SN - 1861-3829

IS - 6

ER -