Arthropod survey on soybean crops in Cambodia: a comparison of the sweep netting and beat sheeting collection methods for estimating arthropod diversity and species richness

Abstract

This is the first assessment of insect assemblages on soybean crops in Cambodia. Sweep netting and beat sheeting collection methods were used to evaluate the effectiveness of sampling arthropods and their collection efficiency in soybean crops and to determine soybean insect diversity and composition at two sites. Overall, arthropod populations sampled by sweep netting were substantially different compared to populations collected by beat sheeting. The sweep netting caught significantly higher numbers of most Orders; however, the beat sheeting caught a significantly higher number of Acari. Beat sheeting was also effective for sampling 'Nezara viridula' which is a major invertebrate pest of soybean. There was a significant interaction between location and collection methods for both Hemiptera and Hymenoptera assemblages. Selection of insect sampling method depends on many factors such as plant type, plant structure, field conditions, ease of use, cost of use and target insect species. However, the sweep netting was best for fast flying insects such as hymenopteran wasps and those located in upper parts of the plant canopy. The use of different sampling methods to assess pest, predator/parasitoid and general community structure in crops is crucial for assessing Integrated Pest Management strategies.