COMMON NAMESombava (Oshindonga); ombuvi (Oshikwanyama,); ombwii ( Oshimbalantu); ombaa (Oshikwambi, Oshingandjera, Oshikolonkadhi)Note: The oshiwambo word "ombava" is used for various pests attacking plants at ground level. Ombava therefore also refers to the larvae of “false wireworm” (beetles), which is not included in this manual. PEST STATUSOmbava is a widespread pest on cereals. It is only of importance in years in which there is a dry period shortly after the crop has germinated. Ombava is found mainly on young pearl millet plants and less frequently on sorghum (there are a few unconfirmed reports that "ombava" could attack legumes such as cowpea and groundnuts as well, but there are some indications that this could represent another moth species.)Only very young plants are attacked. If the attack is severe, the entire plant appears ragged and chewed. In such case many plants will die or be set back. Farmers often reduce the damage by gap-filling with extra plants from the thinning process, but during major attacks, the crop needs to be re-sown. As soon as the rain begins again, the attack is over for that crop and the caterpillars and damage disappear. DISTRIBUTIONOmbava is widespread in all four northern regions: Omusati, Ohangwena, Oshana and Oshikoto. Ombava seems to attack crops anywhere in the area if the rainfall pattern is suitable.DESCRIPTIONThe caterpillar is 10-12 mm long and cream to pale red in colour. The body has red stripes and the head is black. The caterpillar lives in a dense web at the base of young pearl millet plants. The web is often covered with sand and during the day the caterpillars hide underground in tunnels. Pupation takes place in small cells made of soil.The adult ombava is a tiny moth with a wing span of 12 mm. The colour is pale yellow with darker markings at the wing tips. The moth is seldom seen because it is so small. CONTROLOmbava attacks are often reduced by heavy rain. If sufficient rain is expected soon, farmers should wait until the effect of rain can be seen before using other control methods. Missing plants can then be replaced from the next thinning.Some farmers do not weed or thin their crop during an attack of ombava or other pest species. They fear that the weeding will increase the attack of pests. The caterpillars stay underground during the day and are therefore difficult to control through direct application of chemicals. During the 1996/97 season, seeds of pearl millet were treated with a seed dressing (Gaucho) for testing on infested fields. Very few test plots were sown, however, and the effect could not be assessed due to good rains that year.
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