Influence of seasonal changes, weather factors and soil depth on the foraging activities of subterranean termites in Eucalyptus plantations

Abstract

Eucalyptus tree is an important exotic species used for building construction, environmental amelioration and ornamental purposes in the tropics. However, termites cause a great damage and high mortality to seedlings and saplings of Eucalyptus in the field. Information on critical period and soil depth of termite foraging activities is required to formulate effective management programme. In this study, the critical foraging period and depth in the soil of subterranean termites in four different Eucalyptus species plantations was determined using the indices of percentages of baits attacked and consumed at in ground monitoring stations. The results showed that the highest and lowest percentages of baits attacked and consumed by termites were recorded in the months of February–April and August–October, respectively in all Eucalyptus plantations investigated. The critical depth of foraging activities recorded during the months of February–April was from 10 to 40 cm below the soil level as more than 50% and 40% of baits were attacked and consumed, respectively. Bait consumption by termites correlated significantly and positively with mean monthly temperature but correlated negatively and significantly with relative humidity and rainfall. This information on the critical season and depth of termite activities in the soil and as well the influence of weather factors on termite activities should be considered in the formulation of appropriate and effective termite management programme in the establishment of Eucalyptus plantation.