Effect of planting and harvesting dates on fungus-growing termite infestations in maize

Abstract

Fungus-growing termites (Microtermes spp. and Allodontermes spp.) damage maize roots and cause lodging. The pattern of attack, incidence of lodging, and the effect of planting and harvesting dates on damage and yield were studied in field trials over five seasons. The pattern of injury was similar in different seasons, commencing three weeks after crop emergence and increasing to harvest. Variation in planting date had no effect on the pattern or severity of attack. Under conditions of reduced termite pressure, timely harvesting could be done when the incidence of lodging was comparatively low, resulting in reduced labour cost to collect ears from lodged plants. Under severe termite pressure lodging commenced at such an early stage that plants could not be harvested early enough to prevent losses owing to lodging. Lodging is regarded as the most severe symptom of damage by termites although yield loss may also occur if the roots are damaged. Lodging per se did not affect yields but the costs of labour required to collect ears contributed to an overall loss of income. Prolonged flooding conditions reduced the number of damaged and lodged plants.

Keywords:

• harvesting dates
• injury pattern
• maize
• planting dates
• termites