How TZ is battling fall armyworms

Wednesday May 22 2019


By Rosemary Mirondo @mwaikama

Dar es Salaam. The Tropical Pesticide Research Institute (TPRI) has come up with a technology that is specifically meant to control the invasion of Fall Armyworms (FAW).

FAW were first reported as present on the African continent in January, 2016 (Goergen 2016) and they invaded Tanzania in 2017. Subsequent investigations have revealed the pests are now in nearly all of Sub-Saharan Africa (SSA), where they are causing extensive damage, especially to maize fields and to a lesser degree, sorghum and other crops.

Currently, over 30 countries have identified the pest within their borders including the island countries of Cape Verde, Madagascar, São Tomé and Príncipe, and the Seychelles.

Although new agricultural pests are periodically introduced into the African agricultural environment posing some degree of risk, a number of characteristic factors make FAW a more devastating pest than many others.

However, TPRI’s Pest and Pesticide Management senior researcher Maneno Chidega told the Mwananchi Thought Leadership Forum that to help farmers they have started to create awareness and train agriculture officers on the best ways to deal with the situation and what and how to use pesticide.

“We came up with a technology known as fall armyworm symptomatic spraying scheme for Tanzania, a new scheme which stipulates what kind of pesticide can be used during early symptoms of the invasion,” he said.

The FAW are an invasive species that invaded the country in March 2017, and are now in more than 18 regions, farmers are facing a huge challenge because they are not aware of the kind of enemy they are dealing with, said Dr Chidega.

According to him, the FAW are known for their first moves which is to land into a plant and the first thing is to consume the leaves and then going into the wall or funnel to hide and consume the crop while other pest are just contact pests unlike the FAW, which consumes the inside of the crop.

He explained that through the scheme the farmer is advised to use the systemic pesticide that goes direct into the plant killing the FAW caterpillar.

“This scheme is important because it helps farmers to know pesticides to use at early stages but when advanced the technique is to use the systemic pesticide that goes in the plant where the caterpillar may be,” he said.

He noted that the tool is important and 3,000 extension officers have been trained in order to train farmers and they have developed a system post training impact monitoring that ensures that even while at the office or laboratory they can know when farmers are trained with their signatures and the date and location.

“We have been facing challenges whereby after extension officers are trained, we are not sure whether they too pass the skills on or not but with the post training impact monitoring we are sure,” he stressed.

Meanwhile, according to the first edition of Fall Armyworm in Africa: A Guide for Integrated Pest Management FAW consume many different crops. FAW are capable of feeding on over 80 different types of crops, making them among the most damaging crop pests.

While FAW has a preference for maize, the main staple of SSA, it can also affect many other major cultivated crops, including sorghum, rice, sugarcane, cabbage, beet, groundnut, soybean, onion, cotton, pasture grasses, millets, tomato, potato, and cotton.

FAW spreads quickly across large geographic areas. Like other moths in the genus Spodoptera frugiperda, FAW moths have both a migratory habit and a more localised dispersal habit.

In the migratory habit, moths can migrate over 500 kilometres before oviposition. When the wind pattern is right, moths can move much larger distances, for example, a flight of 1,600 kilometres from the southern US state of Mississippi to southern Canada in 30 hours has been recorded (Rose et al. 1975).

FAW can persist throughout the year. In most areas of North America, FAW arrive seasonally and then die out in winter, but in much of Africa, FAW generations will be continuous throughout the year wherever host plants are available, including off-season and irrigated crops, and climatic conditions are favourable.

Although the patterns of population persistence, dispersal, and migration in Africa are yet to be determined, conditions in Africa, especially where there is a bimodal rainfall pattern, suggest that the pest can persist throughout much of the year.

Due to its rapid spread and distinctive ability to inflict widespread damage across multiple crops, FAW poses a serious threat to the food and nutrition security and livelihoods of hundreds of millions of farming households in SSA – particularly when layered upon other drivers of food insecurity.

In Southern Africa, for example, the 2016-17 FAW outbreak arrived just as households in the region were still reeling from the 2015-16 El Niño-induced drought, which affected an estimated 40 million people.

The potential economic impacts of FAW on agricultural productivity across (and beyond) Africa are substantial.

Based on an evidence note published by the Centre for Agriculture and Bioscience International (CABI) in September 2017, in the absence of proper control methods, FAW has the potential to cause maize yield losses of 8.3 to 20.6 million metric tons per year, in just 12 of Africa’s maize-producing countries. This represents a range of 21-53 per cent of the annual production of maize averaged over a three-year period in these countries. The value of these losses was estimated at between $2.48 billion and $6.19 billion.

To date, development and implementation of a coordinated, evidence-based effort to control FAW in Africa has faced a number of challenges. In particular, FAW is a recently introduced pest in Africa.

Therefore, FAW scouting by farming communities and effective monitoring at the country, regional, and continental levels are limited.

In addition to delaying recognition of the pest’s movement through Africa, this lack of surveillance, monitoring, and scouting capacity has delayed efforts to determine several key unknowns about FAW populations on the continent and the dynamics of the pest’s establishment and spread.

The lessons learned from the invasive FAW pest should be identified quickly because they are important for monitoring and interception of future invasive pests. Beyond the challenges of recognizing and characterizing the presence of FAW in Africa, the lack of validated strategies to effectively manage FAW in an African context also poses challenges.

Proven approaches to prevent and avoid FAW are presently limited, and efforts to suppress the pest have largely focused on the application of synthetic pesticides – at times in an indiscriminate manner with high potential to damage human, animal, and environmental health.

Furthermore, education, research, and regulatory processes are yet to be scaled up and effectively coordinated across the continent, so as to rapidly disseminate and support emerging best practices for FAW control as they are identified.