Along with a team of researchers led by Prof. Kebin Li at the Chinese Academy of Agricultural Sciences in partnership with the Chinese Academy of Sciences, Ph.D. student, Nyamwasa Innocent showed that compost, a mixture of organic residues made of manure and animal carcasses is detrimental to crops as it attracts soil insect pests.
A previous ‘ScienceDirect’ report complements it showing that soil insect pests are the leading threat to the production of major crops in East Africa.
Prof. Kebin says that due to their cryptic nature, soil insect pests are very hard to monitor.
“They have anti-predator physiology that makes them invisible to the human eye and hence difficult to fight against. Soil insect pests only appear at night to maximize survival and reproductive success and in daylight, they hide under the ground where they lay their eggs.”
The research showed that it is very difficult to spot soil insect pests including moths and preying mantids that have the ability to camouflage and resemble twigs or leaves.
Nyamwasa said that the pests are attracted by the odor and moist compost matter before it has been used in fields and lay eggs on the compost. Once farmers use compost on their crops, the eggs laid by pests develop into insects and damage crops.
One of the crops that are vulnerable to pests’ attacks is groundnuts given that seeds grow underground and easily give way to pests who usually lay their eggs under the surface.
A 2017 research showed that soil insect pests feed on roots and that there are at least 60 insects per square meter.
A resident of Nyamagabe district reported that the pests in his field simulate a very strong odor matching that of the plants they feed and that renders them undetectable.
The second phase of the research showed that compost odor especially cow dung attracts pests and identified ways of combatting them.
Nyamwasa says the second phase of the research was very difficult to execute since it required making a lot of laboratory tests and applying final products in fields to measure the results especially at night because that is when the pests are more active.
To address the issue of pest-infested fields, the team has discovered alcohol-based solutions that can melt the protective wax covering some of the pests’ bodies and hence lead to their death. One soil insect pest lay between 150 and 200 eggs and only one insect is enough to cause irreparable crop damage.
The research has already been approved by experts from the United States and Austria who said that once the research is published in international scientific journals, the alcohol-based solutions will start being used by farmers.
The team plans on claiming copyright of the research findings in a way that they will be able to control who will make money from it.
Nyamwasa advised Rwandan farmers to avoid preparing compost near fields in order to avoid pests’ attacks. He added that farmers should adopt crop rotation practices and include crops such as maize which make it hard for the pests to reproduce.