Pod sucking bug counts – working out damage potential
Green vegetable bugs (GVB) are considered the most important pod sucking bug pest in pulse crops due to their abundance, wide-spread distribution and rate of reproduction. Other species may not always be as abundant, or quite as damaging, but can still cause severe damage when present in large numbers, although spraying before podfill is unlikely to be economically worthwhile.
To determine the damage potential of the field mix of pod sucking bugs found while sampling, a conversion to green vegetable bug equivalents (GVBEQ) allows an assessment of overall potential damage of a mix of bug species compared to the likely damage of GVB.
If no nymphs are present, the adult counts for each species can be converted to GVBEQ by simply multiplying the sample counts by the appropriate conversion factors:
|Pod sucking bug species||Relative damage conversion factor|
|Green vegetable bug (GVB): Nezara viridula||1.00|
|Brown bean bugs (BBB): Riptortus & Melanacanthus sp.||1.00|
|Redbanded shield bug (RBSB): Piezodorus oceanicus||0.75|
|Brown shield bug (BSB): Dictyotus caenosus||0.75|
If you have nymphs in your fields, a further conversion to green vegetable bug adult equivalents (GVBAEQ) is required, because bug nymphs are less damaging than adults. Remember to take an adequate number of samples to ensure your counts are representative of what is present in the field.
Try your sample numbers in our threshold calculator:
Note: This calculator uses individual nymphal stages. An alternate calculator is available that has combined bug nymph values into small, medium, and large for ease of use. Photos of a range of life stages of these bugs are available on the Podsucking bugs page.