2. The effects on yield and nut shedding of ant and moth exclusion.

Abstract

A trial was carried out on a block of coconuts at Maralumi Estates to test the effect, on yield and nut shedding, of excluding the crazy ant, Anoplolepis longipes, and the coconut spathe moth, Tirathaba rufivena, from palms crowns. There were four treatments, three in the part of the block infested with crazy ants and one in the part without the ant. In two treatments with crazy ants, palm trunks were banded with Osticon R to prevent ants moving to and from the crowns. Palms in one of the banded treatments were trunk injected with monocrotophos to kill spathe moth larvae feeding on the inflorescences. The third crazy ant treatment was a control with no attempt to exclude either the ant or spathe moth. Estimates of female flowers and immature nuts shed as well as yield were made at the start and conclusion of the trial. In the treatment without the crazy ant, shedding was less than 40 percent throughout the trial. This figure represented the level of natural shedding Where crazy ants were not excluded from palm crowns shedding was 75.9 and 68 9 percent respectively at the start and conclusion of the trial. These figures represented natural shedding plus shedding due to spathe moth attack. Banding of palms did not decrease shedding, however injection with monocrotophos decreased shedding by 34 6 percent Initially, the estimated yield in the treatment without crazy ants was twice that of the other treatments. However by the end of the trial, yield in this treatment had declined so that there were no significant differences between any of the treatments.