Armyworms, common early season pests that can potentially comb up maize fields have been once again spotted in Nyagatare District, Eastern Province.
They appeared in Kagitumba marshland, Matimba Sector, Nyagatare District where about 350 hectares have been eaten up.
Armyworm eat cereals such as corn, sorghum, and beans among others.
Last year, the pests heavily damaged residents’ crops across the country.
The Ministry of Agriculture and Animal Resources reported that 15,699 hectares were damaged, representing 24.7% of all the land on which corn, sorghum and soybeans were cultivated.
There are concerns that the pests that started from Nyagatare District may spread across the country.
Nyagatare District’s vice mayor in charge of economic affairs, Steven Rurangwa, said that if nothing is done to avert them the pests may have consequences upon the population.
“We have no food insecurity today, but we fear that 22778 hectares of the district could be affected, which would be bad news for farmers,” he said.
When this infestation started last year, the Rwanda Defence Force (RDF) took the lead in the eradication of the pest by ensuring rapid delivery of required insecticides using planes.
Officer in charge of fighting pest Joseph Higiro in charge of fighting pest and diseases at Rwanda agriculture Board (RAB) asked farmers to follow the instructions of the system of crop rotation which lessen armyworm attack.
Appearance and Life History
Several species of armyworms can be found in the Midwest every year.
However, the development of economically damaging populations depends on a number of factors such as; cropping practices, insect migration patterns, parasites and predators, weather conditions, among others.
For example, several weeks of cool wet weather in the spring favor armyworm development and reduces the normal activity of parasites and predators, thus influencing the growth of armyworm populations.
The adult armyworm is a pale brown moth with a white dot in the center of each forewing.
The young larva is green in color and moves about in a looping motion.
A full-grown larva is dull-green to brown in color with alternating light and dark stripes running the length of its body. Upon reaching larval maturity, it is about 1-1/2 inches (38 mm) long.
The larvae feed primarily on grain crops and grasses, attacking other plants only when preferred foods are not available.
Infestations usually develop in grass pastures, fence rows, roadsides and in small grain fields where crops have lodged or are matted against the ground. Once the larvae have consumed the readily available food, or small grains mature, they move into other crops, most notably corn.
This usually happens during May and early June. An exception to this pattern may develop in no-till corn fields where cover crops are used, or in corn fields with many grassy-type weeds.
Armyworm moths are attracted to the grasses in these fields for oviposition. When the larvae hatch in these fields, they can immediately cause damage throughout the field.
This is in contrast to their appearance along the edges of tilled corn fields.
Armyworm larvae usually feed at night and during cloudy days, hiding beneath crop debris or in the whorl of plants at other times.
Because of their nocturnal habits, their presence may not be realized until the crop begins to show feeding damage.
Armyworm feeding gives corn a ragged appearance, with defoliation occurring from the leaf edge toward the midrib.
Damage may be so extensive that most of the plant, except leaf midribs and the stalk, is consumed. Such a highly damaged plant may recover, however, if the growing point has not been destroyed.