- Black beetle adults are a sporadic but very damaging pest in seedling maize with numbers as low as 1/m2 causing economic losses.
- Climate limits the distribution of black beetle to the northern area of the North Island including coastal strips into Taranaki and Hawkes Bay.
- climate also has a huge impact on beetle numbers. Abnormally warm and dry summers in succession lead to an explosion in numbers and a corresponding increase in damage.
- Damage is characterised by a rough, rasped appearance of the plant tissue in the bottom 3cm of the stem.
- Control of black bettle damage can be achieved by delaying planting until mid November or the use of an insecticide.