Scientists in Uganda have devised a way of detecting pests embedded in the roots of bananas through use of of digital camera, a timely move meant to contain pests responsible for over 40 percent of yield losses, and offering hope to the over 10 million East Africans who rely on the crop for food and livelihood.
Traditionally in order to assess the damage of the pests, scientifically referred to as nematodes, one would have to uproot the entire crop, get the roots and analyse the parasites. But with the new technology, digital camera images can be used to detect stresses hindering the growth of tall crops like banana by just measuring the leaf cover.
In the study, a digital camera fitted with a semicircular lens was used to measure the area of canopy leaves for banana crop. The parasitic worms were added to the soil around half the crops prior to field planting. After 106 days, photos of the canopy were taken from the ground and used to generate a leaf area index (LAI). This process was repeated fortnightly for two cropping cycles.
The plantain that were infected with nematodes had lower LAI values than those that were not, according to the study, and these were linked to the stress caused by the parasite by assessing the number of nematodes in the roots and the effect they caused.
Elvis Mbiru, one of the authors and a researcher at the International Institute of Tropical Agriculture in Uganda said that the study proved that LAI correlates with leaf and root development and yields.
"We assume that if the roots are damaged and the leaves are healthy, the yields may be unstable, but this technology helps us understand this better," he said.
The technology could now make it easier for scientists to assess the health of tall crops, as camera images can be rapidly turned into LAI estimates using computer software.
Nematodes are catastrophic to banana farmers because unlike other pests, they attack the roots and the symptoms on the plant are evident when its already too late. Early symptoms caused by these root feeding pests include stunted plant growth, decreased vigor and yield, premature leaf drop and an increased tendency to wilt or dieback during dry periods.
Majority of farmers in East Africa, buffeted by the pest are forced to uproot all infected plants, grow a break crop, and then replant with pest-free bananas because the pest spreads faster across other plantains.