Evolution and status ofOecophylla smaragdina(Fabricius) as a pest control agent in citrus in the Mekong Delta, Vietnam

Abstract

Citrus farmers in the Mekong Delta have a long tradition of managing the weaver ant Oecophylla smaragdina (Fabricius). From 1994 to 1998, insecticide use increased significantly (P < 0.01) from 66% to 84% in orchards where O. smaragdina occurred. In 1998, ca 75% of the sweet orange (Citrus sinensis) and 25% of the Tieu mandarin (C. reticulata) orchards had large O. smaragdina populations, due to lower pesticide pressure in the first crop. In orchards with O. smaragdina, farmers sprayed less frequently and used fewer highly hazardous insecticides. Major insecticides used in sweet orange were monocrotophos and alpha-cypermethrin, and those used in Tieu mandarin were methidathion, imidacloprid and fenpropathrin. Expenditure on pesticides was reduced by half when O. smaragdina was abundant, without affecting either the yield or the farmers' income. Therefore, O. smaragdina husbandry is a good example of a traditional practice which should be further promoted as an important component of sustainable citrus production. The experience of those farmers who use no or few pesticides should be drawn upon in developing farmer training programmes or mass media tools to promote IPM in citrus. Farmers practicing ant husbandry were significantly older than those not doing so.

Checklist of Social (Polistinae) and Solitary (Eumeninae) Wasps from a Fragment of Cerrado “Campo Sujo” in the State of Mato Grosso do Sul, Brazil

“…pollination (Van Mele & Cuc, 2000). According to Pickett and Carpenter (2010), this cosmopolitan subfamily has 958 described species in 26 genera, but the main diversity is in the Neotropical region, mainly in Brazil, with 21 genera and 304 recognized species (Carpenter, 2004).…”

Ant diversity (Hymenoptera: Formicidae) and predation by ants on the different stages of the sugarcane borer life cycle Diatraea saccharalis (Lepidoptera: Crambidae)

“…This study of ants feeding on eggs and immature borers of D. saccharalis revealed that, in plantations where the sugarcane straw is left on the ground in the crop, the immature stages of the borer prior to boring into the stems of sugarcane are at risk of being eaten by ants as: (1) baits of immature borers attract a greater number of ants; (2) ants are most abundant in the morning, both at baits consisting of eggs and immature individuals; (3) ant abundance varies from month to month and (4) Crematogaster sp.7, Pheidole sp.35 and S. saevissima are potentially important predators, given that they are commonly used to control pests (Way & Khoo, 1992;Van Mele & Cuc, 2000;Dejean et al, 2003).…”

Ants as predators of the egg parasitoidTrichogramma cacoeciae(Hymenoptera: Trichogrammatidae) applied for biological control of the olive moth,Prays oleae(Lepidoptera: Plutellidae) in Portugal

“…Ants are known predators of insect eggs (Rossi & Fowler, 2000;Van Mele & Cuc, 2000, 2001Way et al ., 1992Way et al ., , 1999. However, their action was not always beneficial.…”