Cassava is one of Africa’s most widely cultivated staple crop grown on an estimated 80 million hectares in over 34 African countries. In this post, we will highlight the different types of pests and diseases of cassava In Nigeria and how to control them.
High infestation of pest and diseases on the cassava plant can be very drastic resulting in a reduction of the quality and nutritional value as well as a loss of crop yields at harvest.
In our previous post, we highlighted that the cassava plant is of a growing importance to the economy as it serves as a source of livelihood to most farmers, valued as a commercial, industrial and export crop.
A loss in crop yield at harvest due to the attack of pests and diseases will be a painful loss both financially and physically to the farmer, hence the purpose of this post.
To control the attack of pest and diseases, an understanding of what they are is paramount for a successful crop production.
List Of Pests and Diseases Of Cassava and Their Control
These are the insects most likely to affect cassava as well as their control technique:
There are two types of mealybugs;
Feeds on cassava plants (stems, petioles and leaves) and injects a toxin resulting in leaf withering, stunted growth and a loss in crop yields of over 60%.
According to the FAO , a serious outbreak of mealybug in Thailand in 2009 was overcome rapidly by the release of 3 million pairs of Anagyrus. lopezi across the infested area. This is a species of parasitic wasp used as the biological control agent against the cassava mealybug.
Sucks sap of cassava plant but does not inject any toxins into the plants, unlike the cassava mealybugs. The effect of this pest is not as much as the cassava mealybug. It is mostly found on the stem, underneath the leaves or near the petioles.
Some species of these pests attack the cassava plant by sucking the sap of the plant. This leads to a reduction in the crop yields as well as loss of vigour.
Thrips can be controlled using insect growth controllers and chemicals.
3. Cassava shoot fly
They damage the tip of young cassava plants majorly at the beginning of the rainy season. This results in stunted growth of young plants.
4. Larger Grain Borer
The larger grain borer attack mostly during the rainy season by infesting cassava chips in storage, thereby resulting in weight losses as high as 70%.
To control, store cassava with botanicals or plant parts.
5. Cassava Scales Insects
The scale insect covers the stem with conspicuous white secretions, sucks from the stem and dehydrates it. This attack on the cassava plant results in pale and wilt leaves which eventually falls off. This also leads to a drastic loss in crop yields and stunted growth as well as the death of cassava stems in most cases.
To control, destroy infested stems when found, apply organic matter to improve on soil fertility and endeavour to select stem cuttings free from scale infestation.
6. Lace bugs
They attack during the dry season especially in the era of drought. They feed on leaves causing it to fall off. The rate of photosynthesis decreases too. The adults and nymphs are mostly found underneath the leaves.
7. Leaf-Cutting Ants
These ants attack the cassava plants by cutting out pieces of the leaves and buds which they sometimes carry back to their nests. Pest infestation usually occurs at the first month of growth. To control, apply insecticides.
Female grasshoppers lay their eggs just beneath the surface of the soil and when they hatch they begin to feed on the cassava plants, chew the leaves and stems. Pest infestation may also destroy or cause widespread loss of leaves.
Pest infestation usually occurs during the dry season. While they chew and eat up stem cuttings of younger plants leading to stunted growth, rot or death, they chew and enter into the stems of matured plants resulting to weak stems which will eventually break off.
To avoid attack, plant early with the rains rather than dry lands.
10. Chinch Bug
The chinch bug is a common pest that attacks crops. They live in the soil and attacks plant by making a hole in the tubers, thus reducing the nutritional value and quality of the cassava plant.
This bug can be controlled using fertilizers as well as cultivating the crotalaria plant alongside cassava plant.
They attack cassava plant by sucking the sap from the cassava leaves. They excrete large amounts of honeydew which supports the growth of black sooty mould on the plant, resulting in premature fall of leaves and loss of crop yields of over 70%. The adult and nymphs of this pest occur in large numbers on the surfaces of older leaves covered with white waxy material.
Several species of these whiteflies are found in Africa.
To control, use natural enemies of this pest such as the parasitic wasp.
Other pests of cassava include white-grubs, gall midges, domestic animals such as cattle, goats, sheep, pigs, rodents, monkeys and birds.
They can be controlled by weeding your farmland regularly, making use of farm fence, traps etc. Endeavour to harvest crops as soon as they are matured enough.
Some of the diseases of cassava plants include;
- Brown and white leaf spot diseases
- African Cassava Mosaic Disease
- Cassava bacterial blight disease
- Root rot diseases
- Cassava anthracnose disease
- Cassava bud necrosis
High infestation and upsurges of these pests and diseases of cassava, can result in huge losses in crop yields, thus posing a threat to the economic value of the cassava plant and nutritional security.