2013, Pol, Chanthy, Martin, Robert, Gunning, Robin V, Andrew, Nigel R

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.

2012, Pol, Chanthy, Martin, Robert, Gunning, Robyn V, Andrew, Nigel R

According to geographical distribution, 'Nezara viridula' (Heteroptera: Pentatomidae) can be found across tropical, subtropical, and temperate regions and this pattern is assumed to reflect differences in thermal adaptation, particularly in cold tolerance. Here the lethal temperature (LT) and critical thermal limits (CTL) (thermal tolerance) are examined for 'N. viridula'. The upper LT for 'N. viridula' at two contrasting climate locations (Breeza and Grafton, New South Wales, Australia) was 40.3°C with 20% survival under the stress of high temperature. The lower LT did not differ between these two populations and was -8.0°C with 20% survival under low temperature stress. Survival of 'N. viridula' increased after acclimation at high temperature for 7 days. In contrast, when acclimated at lower temperatures (10 and 15°C), survival of Breeza and Grafton 'N. viridula' was lower than 20% at -8.0°C. Control-reared 'N. viridula' adults (25°C) had a mean CTMinOnset (cold stupor) of 1.3 ± 2.1°C and a mean CTMax (heat coma) of 45.9 ± 0.9°C. After 7 days of acclimation at 10, 20, 30, or 35°C, 'N. viridula' adults exhibited a 1°C change in CTMax and a ~1.5°C change in CTMinOnset. CTMax and CTMinOnset of Breeza and Grafton 'N. viridula' populations did not differ across acclimation temperatures. These results suggest that short-term temperature acclimation is more important than provenance for determining LTs and CTL in 'N. viridula'.