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May 2017. An article appeared in the Guardian 20 May (or thereabouts) https://www.theguardian.com/global-development-professionals-network/2017/may/16/armyworms-the-hungry-caterpillar-threatening-a-global-food-crisis, and was heavily critized by Pestnet members. The original article is given below, and members’ response follow.
Ernst Neering wrote:
This article is bullshit. Neither the author of this article nor any of the people commenting on it seem to be knowledgeable about the problem. It would have been better if the people quoted by the author could have had their say unedited, big chance that the information would have been more accurate and less a horror novel.
First find was in Sao Tome, subsequently it was found in Nigeria, Togo and Benin. East and Southern Africa followed, so did Ghana and recently Cote d’Ivoire. There is report that it may have reached Ethiopia (not yet officially confirmed).
Young larvae are easily killed, it is the later instars that are difficult to manage. On maize, the caterpillar stays in the whorl, on other crops (what is that picture of cocoa harvesting doing in this article?, that is not a hostplant !) they shelter in the soil at daytime. On groundnut they can be found on young developing pods, and then always staying in the ground which makes them difficult to be found by natural enemies.
In the Americas, on maize, earwigs are important predators. Predatory wasps and birds feed on the larger caterpillars, but then mainly on other crops than maize. The parasitic wasp Telenomus remus has been employed as biocontrol agent (inoculative releases were made in many countries, yet no mention yet about possible introduction in Africa), other parasites, such as ectoparasitic Braconidae, seem less effective. Nuclar polyhedroviruses have been found effective, Bt-crops have been the major management option in the America’s though their effectivenes is not as good as previously anymore (resistance to Cry1A seems to be developing). The implications of the possible splitting of the species are not yet fully understood: the “maize strain” seems to stick more to cereals, while the “rice strain” also goes to other plants. It is too early, the invasion too recent, to know what management options will be feasible for eppication under the conditions prevailing in the invaded African countries.
Hopefully, future articles on this pest will be descriptive of facts and not just describing Armageddon or Pandora’s box, but also offering options for management of this pest.
I hope knowledgeable people will elaborate further.
Matthew Cock wrote:
To answer one specific point, Ernst, I think the image of cocoa has got in there because there is another caterpillar outbreak on cocoa in Ghana at the moment (or very recently), which Victor Clottey of our Ghana office tells me is Anomis, although in the local press it has been called armyworm. I have seen images which suggest he is correct – certainly they show that it is not Spodoptera frugiperda.
The Guardian article.
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