Reducing losses inflicted by insect pests on cashew, using weaver ants as a biological control agent

Abstract

* In Benin cashew plantations, yields and nut quality are lost mainly as a result of insect pests. In the present study, we investigated the effectiveness of the African weaver ant Oecophylla longinoda as a biocontrol agent against Beninese cashew pests. * In a 2-year study, nut yield and quality were compared among: (i) trees with weaver ants O. longinoda; (ii) trees where weaver ants were sugar-fed; (iii) integrated pest management (IPM) trees with weaver ants combined with fruit fly bait spray; and (iv) control trees receiving no control measures. * All treatments with ants showed significantly higher yields than the control, with the IPM treatment leading to the highest yield. Compared with the control trees, the ants, ant sugar-fed and the IPM trees produced 78%, 122% and 151% more nuts, respectively. Nuts produced on control trees were of a higher quality on average because they were less damaged by thrips (probably because the fruit fly bait worked as a contact poison on thrips); this was also the case for the IPM treatment. In absolute numbers, however, trees in ant treatments produced more first-quality nuts. * To achieve a broader and effective control of both coreid bugs and thrips, a combination of weaver ants and supplementary compatible control measures is recommended. (Résumé d'auteur

The use of extrafloral nectar in pest management: overcoming context dependence

“…The plant has been described as providing a 'movable feast' for ants (Tilman 1978;Fiala & Maschwitz 1992), shifting their foraging habits, temporally, towards sites most susceptible to herbivory. Interactions between cashew and weaver ants, Oecophylla spp, have been the focus of many studies, and the potential to harness these interactions for pest management has been explored over a large geographic range (Peng, Christian & Gibb 1995;Dwomoh et al 2009;Olotu et al 2013;Peng, Lan & Christian 2014;Anato et al 2015).…”

“…Damage from a range of important economic pests was reduced in the presence of ants, and in the case of mosquito bugs, blue shoot borers and fruit-nut borers, ants provided a level of control equivalent to that achieved through the use of insecticides. Anato et al (2015) studied the effects of weaver ants in cashew plantations in Benin. Not only did the presence of ants increase nut yield, but the benefits of ants were enhanced through the provision of dietary subsidies (30% sucrose solution).…”

“…Not only did the presence of ants increase nut yield, but the benefits of ants were enhanced through the provision of dietary subsidies (30% sucrose solution). Nut yields were highest of all when ants were incorporated into an integrated pest management programme that included spot spraying with insecticides (Anato et al 2015).…”

Weaver Ant Oecophylla longinoda Latreille (Hymenoptera: Formicidae) Performance in Mango and Cashew Trees Under Different Management Regimens

“…We therefore find it safe to conclude that Spinosad in the form of GF-120 and applied as described here and in Anato et al (2015), is compatible with the use of weaver ant. This is of importance as spinosad have proven effective against fruit flies in mango (Prokopy et al, 2003;Wang et al, 2005;Vayssières et al, 2009) and against thrips in cashew (Anato et al, 2015) and since these species are important pest in West Africa (Vayssières et al, 2008;Anato et al, 2015), the efficiency of pest control may be advanced by combining weaver ants with GF-120. This is in concordance with previous studies demonstrating that GF-120 had no detectable effect on beneficial insects such as the parasitoids Aphytis spp (Thomas & Mangan, 2005) and Fopius arisanus (Sonan) (Vargas et al, 2002).…”

“…In Northern Benin, mango and cashew are the most important tree crops with high economic importance (Vayssières et al, 2008;Balogoun et al, 2014). Recently, pest control by weaver ants has been observed in mango and cashew (Adandonon et al, 2009;Van Mele et al, 2007;Anato et al, 2015) and here the fruit fly bait GF-120 has been identified as an effective supplementary IPM component that in combination with weaver ants may lead to better control of pests such as fruit flies and thrips Anato et al, 2015). At the same time GF-120 is an environmentally safe insecticide to use.…”