A Zambian agriculture technology company has taken it upon itself to help eradicate the armyworm plague in the country.

Operating out of the capital city of Lusaka, Sunagri Investments has seen its fleet of mainly XAG drones traversing the country to rid maize and sugarcane fields of the deleterious pests, at all hours of the day.

“We usually deploy our drones for operation after sunset, when the nocturnal pests come out of hiding,” said Fraser Zhang, founder of Sunagri. “During daytime, the fall armyworm caterpillars usually hide inside the central part of corn and sometimes burrow into the soil. When they grow older, they would generate large quantities of frass to block the whorls, making it difficult for chemicals to reach the pests.”

He added. “But, with intelligent atomisation of the spraying system, our drones can target pesticides uniformly onto the leaves, whorls and stems of the corn. Of course, low-toxicity systemic insecticide would be more effective to increase pest mortality and protect the plants.”

The African armyworm is a moth whose larvae often exhibit marching behaviour when traveling to feeding sites, leading to the common name armyworm. The caterpillars exhibit density-dependent polyphenic traits during development, where larvae raised in isolation (solitaria) are green, while those raised in groups (gregaria) are black. It is the gregaria caterpillars that are deadly, as they are capable of destroying entire crops in a matter of weeks. The larvae feed on all types of grasses, on young cereal crops like corn, rice, wheat, millet, sorghum; on sugarcane, and occasionally on coconut.

The African armyworm is commonly found in the grasslands of Africa and Asia. Within Africa, it is mostly seen near the Sahara in the following countries: Tanzania, Kenya, Uganda, Ethiopia, Somalia, Malawi, Zimbabwe, Zambia, and South Africa. Outside of Africa, the species also inhabits southwest Saudi Arabia, Southeast Asia, Australia, and New Zealand.

Armyworm outbreaks tend to be devastating for farmland and pasture in these areas, with the highest-density outbreaks occurring during the rainy season after periods of prolonged drought.

And with droughts being a frequent visitor to Southern Africa of late, the armyworm has been a yearly bane on crops in the region, feasting on its favourite maize meal, which also happens to be the staple food of Southern Africa. In Zambia, farmers were losing the annual fight against the armyworm, until Sinagri decided to premier a new spraying method to replace the traditional insecticide spraying. According to the country’s ministry of Agriculture, fully 98 percent of farmers polled in Zambia and Ghana confirmed that their maize crop was affected, and the average maize loss was 35 percent – a loss of nearly $16million. In the 2019 farming season, 46 districts and 521 farming settlements sent out distress calls.

Sinagri responded with drones.

Zhang said he realised that the combat against fall armyworm needed to go aerial. So, he reached out to XAG for its precision UAS spraying solution. During last years’ growing season, his team conducted a series of field experiments and practical operations on three commercial farms, covering approximately 200 hectares of croplands.

Spoiler alert; it worked a treat. At Kalele Farm in Kabwe in the Central Province, fall armyworms were successfully defeated on 30 hectares of heavily infested cornfield.

Said Zhang; “The farm manager thought his maize crops couldn’t stand a chance against the pests and decided to hedge his bets on our new technology. We utilised the spraying drones to apply chemical treatment twice, and the result were satisfactory, as a yield loss was avoided.”

Now with a few years of accumulated experience on UAS crop protection, Sunagri have seen their operations starting to grow in the country, having made the drone-based spraying service a darling of more local companies and commercial farms, which include Zambia Sugar, Kasama Sugar, York Farm, Butter Mere Farm and Seedco. Zhang says his drone sprayers are in demand all over the country, and they have obliged in return, braving all kinds of weather and accommodation challenges; all for the good of the maize fields.

With growing operations, the company has also started transferring knowledge to native Zambians, training them on drone flying and maintenance.

Another thing to consider when incorporating drone technology has been the safety of farmers from chemicals. Growing up in rural and farm areas, one can still remember parents, small scale farmers in their own right, saddled with a yellow spraying pack on their back, walking the length and breadth of their plots, applying chemical spray to their crop. So it has been with many a small scale farmer in Zambia too. But obviously, this is not a safe for the farmers who have to stay in constant contact with the spray, and is ineffective when trying to ward off pests with strong migration and reproductive ability.

“Besides, it is impractical to conduct manual spraying over farmlands larger than 5 hectares, let alone a massive waste of pesticides and the risk of chemical poisoning,” Zhang added.