Pests > Pests Entities > Insects > Moths & butterflies > Spodoptera species > Natural enemies of FAW

Natural enemies of FAW

November 2017. An article in the Thomson Reuters Foundation at
http://news.trust.org/item/20171105182703-sv3ue/ Suggests among other things that were are no natural enemies of the fall armyworm. This was commented upon by members.

This is totally untrue. There are a whole range of egg, egg larval, ecto and endo larval, larval pupal and pupal parasitoids and predators like species of Chrysopids, Carabids and Vespids. The most effective of these in my opinion is the egg parasitoid Telenomus remuswhich is easily mass reared and could be released in the millions against this pest. What is most irritating is the constant discussion about what needs to be done or could be done and nobody’s doing anything. Telenomus remus, for example, could be reared cheaply and released in the millions.

Other members agreed. It is difficult to see how or where a well focused. multifaceted faceted action plan is developing, Conventional biological control is one option but there are other approaches that could or need to be instigated – it has been done before, successfully, with similar pest problems.

The example of Spodoptera mauritia in corn in north Cambodia was given. Until research proves other techniques (for example, proven economic action thresholds, resistant cultivars, pheromones, etc.) simple controls based on ‘scout and squash’ canbe suggested. Walk the crop twice weekly and squash (or spot spray) egg masses and small gregarious larvae. If and when the caterpillars get to damaging sizes then may need apply insecticides. Active ingredients (cyantraniliprole and chlorantraniliprole) are less toxic to biocontrol agents. There are other selective insecticides such as indoxacarb, spinosad and even fipronil (only apply on non-flowering plants). Also, might be worth placing caterpillar bait granules into the lower whorls of corn. This is done in corn crops in Vietnam, using fipronil baits. ‘Scout and squash’ mainly works when the crop is young.

As a parallel problem, that of Spodoptera litura in peanut in India was given. Ten years later after collaboration from some switched-on ‘lead farmers’, NGOs, Farmer Support Groups, some bright students from Europe, and a strong home team the problem was licked. Specifically, stop applying insecticides and find and demonstrate ways to encourage predators such as ladybirds and (real) birds into the fields. Nuclear polyhedrosis virus was a also an unseen contributor. The same principles also applied in SE Asia. The success was based on basic research to understand the ecology of the insect and its natural enemies and an understanding of te farmers their farming systems.

One member has just returned from THe Democratic Republic of the Congo, and this is his account. There is an abundance of stalk borer in areas where the FAW has not arrived yet, and there is a lot of Spodoptera exemptain areas where FAW is present and maize is grown. So for the general public it is not that easy to distinguish. In Northern and Southern Kivu FAW is also found on rice and is quite devastating (although not yet identified molecularly). In many areas, maize is about the only crop that is grown because other crops, e.g., manioc is no longer grown. The farmers have no clue what to do with FAW and so they use pesticides if they have them. All interventions have to be assessed against the time it takes for control. Scouting, looking for frass windows on leaves, eggs, nymph masses and all that has to be shown, taught, followed. Crushing eggs and whatever else of FAW sounds easy, but people have time constraints, with many other things to do. Using pesticides is easy – if you know the right ones, the safety of application, mixing and all that. Biopesticides, e.g., Spinosad, even Neem, can work, but you need to give training. And as for the recommended CIMMYT hybrid, they will be immediately planted if they were available. Solutions have to come now, and it seems they will take time.

World food prize delegates convene