Optimising methods for collecting beneficial Hymenoptera in orchards

Ngaire Larsen *1, Alastair Robertson 2, Maria Minor 2

1 Plant and Food Research, 71 Landscape Road, Mt Eden, Auckland 1024, New Zealand
2 Massey University, PB 11222, Palmerston North, 4442, New Zealand

Insects are monitored in agricultural systems for the purposes of detecting pest or beneficial species.  The methods by which pest species are caught have had much time devoted to them and as a result a large number of traps, particularly pheromone based, targeting specific pests have been developed.   Beneficial species have not been the subject of nearly as much testing; consequently, far less is known about the most effective methods of generalised monitoring of beneficials.  I monitored four groups of beneficial Hymenoptera during February 2009 in three organic apple orchards in the Hawkes Bay, New Zealand.  Each hymenopteran group was assessed for their attraction to trap type, trap colour, preservative type and their distribution within the orchard with regards to the shelterbelt.  I found yellow sticky traps to be the most effective trap type overall for sampling the order Hymenoptera, and the two parasitoids Anagrus sp. (Mymaridae) and Aphelinus mali (Aphelinidae).  White pan traps were most effective at sampling Halictidae (Apoidea).  Sodium benzoate was a more effective preservative in pan traps than propylene glycol. Most Hymenoptera were found to be more abundant within the orchards than at the shelterbelt, excepting the Halictidae.  In order to effectively sample particular beneficial species, prior testing should be done in order to find the most effective trap types and colours. Monitoring these beneficials in organic environments is important, so that their potential effectiveness in controlling pests can be gauged.  

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