Army­worm war needs new tac­tic

Africa should turn to lower risk so­lu­tions to fight the pest which is en­dan­ger­ing food se­cu­rity and liveli­hoods

The Star Late Edition - - METRO - MELANIE BATE­MAN

THE CATERPILLARS of the fall army­worm (Spodoptera frugiperda), an in­va­sive moth, can po­ten­tially feed on more than 350 species of plants. In the Amer­i­cas it’s known as a se­ri­ous pest.

It de­stroys crops of maize, rice, sorghum, sugar cane, peanuts, soy­bean and non-food crops such as cot­ton. In maize, fall army­worm feeds on the de­vel­op­ing leaves and then the grains, dam­ag­ing the plant and re­duc­ing yield.

It was found only in the Amer­i­cas. But in 2016 it ap­peared in West Africa and is in more than 40 coun­tries in trop­i­cal and south­ern Africa. It has also re­cently been re­ported in In­dia.

Re­search map­ping en­vi­ron­men­tal suit­abil­ity shows that large ar­eas of Asia are suitable for fall army­worm, in­clud­ing parts of In­dia and China, the world’s sec­ond-largest maize pro­ducer.

The pest presents a threat to food se­cu­rity and its im­pact on maize alone could dev­as­tate the liveli­hoods of tens of mil­lions of farm­ers. Es­ti­mates sug­gest that the po­ten­tial yield loss due to fall army­worm in 12 coun­tries would be huge. The data show that be­tween 4 mil­lion and 18 mil­lion tons an­nu­ally out of an ex­pected pro­duc­tion of 39 mil­lion tons could be lost.

The eco­nomic cost is es­ti­mated to be from $1 bil­lion (R14bn) to $4.6bn a year.

To pro­tect their food sup­plies, African coun­tries are putting in place large-scale emer­gency mea­sures. Many of these fo­cus on the wide­spread dis­tri­bu­tion and use of pes­ti­cides. But this isn’t the ideal so­lu­tion for a num­ber of rea­sons. First, some pes­ti­cides are harm­ful and toxic. Sec­ond, pes­ti­cides put many small­holder farm­ers at risk – many aren’t fa­mil­iar with the prod­ucts and might lack the pro­tec­tive equip­ment to pre­pare and ap­ply them safely.

There are other lower risk al­ter­na­tives. One of these is biopes­ti­cides – nat­u­rally oc­cur­ring sub­stances or or­gan­isms that kill pests. In a re­cently pub­lished study we show that biopes­ti­cides present safe, low-risk op­tions which can serve as vi­able al­ter­na­tives.

Biopes­ti­cide prod­ucts to con­trol fall army­worm are com­mer­cially avail­able in the Amer­i­cas and are used by farm­ers in North and South Amer­ica. Some African coun­tries are also mov­ing in this di­rec­tion. For ex­am­ple, South Africa has pro­vi­sion­ally reg­is­tered sev­eral biopes­ti­cide prod­ucts for use against the fall army­worm, and biopes­ti­cide tri­als are un­der way in many other coun­tries.

Our study as­sessed more than 50 biopes­ti­cide ac­tive in­gre­di­ents which have been reg­is­tered in fall army­worm’s na­tive range in the Amer­i­cas as well as in some African coun­tries. We re­viewed the lit­er­a­ture and reg­u­la­tory doc­u­ments with the aim of an­swer­ing five key ques­tions: Is the biopes­ti­cide ef­fec­tive against fall army­worm? Is it of low risk to hu­man health and the en­vi­ron­ment? Is it sus­tain­able? Is it prac­ti­cal for use by small-holder farm­ers? Is the biopes­ti­cide avail­able?

We iden­ti­fied 23 ac­tive in­gre­di­ents that we rec­om­mended for fur­ther con­sid­er­a­tion. We also iden­ti­fied eight ac­tive in­gre­di­ents that should be brought to mar­ket. These in­clude prod­ucts con­tain­ing neem plant ex­tracts and Bacil­lus thuringien­sis, two of the most widely used biopes­ti­cides glob­ally. This in­cludes fast-track­ing prod­uct reg­is­tra­tion, as well as re­view­ing and up­dat­ing in­for­ma­tion ma­te­ri­als and rec­om­men­da­tions for farm­ers, as well as tak­ing into ac­count avail­abil­ity.

More needs to be done if biopes­ti­cides are go­ing to re­place chem­i­cal pes­ti­cides. For ex­am­ple, in the medium-term, gov­ern­ments will have to as­sist farm­ers by sub­si­dis­ing biopes­ti­cides, an ap­proach be­ing adopted by Ghana. They could con­sider lo­cal pro­duc­tion of biopes­ti­cides, work­ing in part­ner­ship with the pri­vate sec­tor.

There are a host of chal­lenges too. Few biopes­ti­cide prod­ucts are reg­is­tered for use in African coun­tries. And most of those reg­is­tered aren’t widely avail­able or af­ford­able, par­tic­u­larly for small­holder farm­ers. While some farm­ers might be will­ing to pay a premium for a lower risk prod­uct, many small­hold­ers have such small mar­gins that they will seek to min­imise pro­duc­tion costs. So older, off-patent and cheaper pes­ti­cides might be pre­ferred, de­spite the dan­gers.

With greater sup­port from gov­ern­ments, re­search, the pri­vate sec­tor and NGOs, a mar­ket for lower risk prod­ucts could be de­vel­oped, which would lower prices. Ul­ti­mately, biopes­ti­cides present an op­por­tu­nity to lower not just the eco­nomic cost of con­trol­ling fall army­worm, but also the cost to the en­vi­ron­ment and hu­man health.

Such an ap­proach should fit into a broader drive to con­trol fall army­worm by us­ing a more in­te­grated ap­proach that com­bines a va­ri­ety of agri­cul­tural prac­tices. Known as in­te­grated crop man­age­ment, the ap­proach in­volves com­bin­ing a range of prac­tices with an em­pha­sis on those re­garded as “low risk” com­pared to con­ven­tional chem­i­cal pes­ti­cides.

This could in­clude closely mon­i­tor­ing the crop, in­ter­crop­ping, man­ual re­moval, bi­o­log­i­cal con­trol, in­sect-re­sis­tant va­ri­eties and tra­di­tional meth­ods such as ap­ply­ing ash. | The Con­ver­sa­tion

Dr Melanie Bate­man, lec­turer in ICM Master’s pro­gramme on jointly or­gan­ised by CABI, Univer­sity of Neuchâ­tel, Switzer­land. Roger Day, pro­gramme ex­ec­u­tive at CABI, also con­trib­uted to this ar­ti­cle.

A FARMER in Bubi, near Bu­l­awayo, Zim­babwe, shows the dam­age to his maize crop caused by the fall army­worm. | AARON UFUMELI EPA African News Agency (ANA) Archives

Newspapers in English

Newspapers from South Africa

© PressReader. All rights reserved.