Maize suffers from a number of insect pests that usually leads to reduction in yield of the plant. In many African countries, the average maize yield per hectare is very low. These insect pests of maize cause damage to the plant and these cause stress to the plant. For maize, threatening organisms are stem borers, nematodes, bacteria, viruses, fungi and weeds are some of the organisms that have negative impact on the maize plant.
We look at some of the major insect pests of maize and the damages they cause to the maize plant and how they can be controlled or managed.
African maize stem borer (Busseola fusca)
Larvae feed in whorls, causing small windows after the leaf grows out, and some leaves are even rolled up.
The larvae tunnel into the stem and inside the stem. Larvae can also tunnel into the ears, leading to direct yield losses. Feeding on kernels may also lead to downgrading of the harvest.
Control
Destroy volunteer and alternative hosts to eliminate stem-borer. Crop rotation with groundnut, sugarcane or cotton is very effective against stem-borer.
Grow resistant varieties
Apply Carbonfurn 3G at 3kg per acre.
Aphids (Raphalosiphum maidis
Both nymph and adult suck the sap from the plant especially the leaves. This turns the leaves yellow and in the case of heavy infestation, the plants remain stunted. Their injury causes oozing of sap which crystallizes on evaporation forming a sugary material called sugary disease.
Control
Coccinelids and chrysophiids suppress the population of nature.
However, you need base treatments with dimethoate 2 ml/l or monocrotophos 1.6ml/l or acephate 1g/l.
African pink stem borer (Sesamia calamistis)
The larvae penetrate the stem shortly after they emerge from their eggs.
The larvae can tunnel into the stem, resulting in broken and/or drying stems, and eventual death of the growing point. During ear filling, the majority of the larvae are in the ears.
Control
Pull out and destroy by burning dead hearts and affected plant part.
Place granules in the central whorls.
Apply Carbofuran 3G, Carbaryl 5G at 12kg/ha in the leaf whorl three times at 20, 30 and 40 days age of the crop.
