Dispersal of Aphytis melinus (Hymenoptera: Aphelinidae) after augmentative releases in citrus orchards

Abstract

Abstract. The efficacy of natural enemies in controlling pests under field conditions is largely correlated with their capacity to spread within infested crops. In this study the spatial dispersal of the California red scale parasitoid Aphytis melinus DeBach (Hymenoptera: Aphelinidae) was evaluated in the field after augmentative releases. The experiment was conducted in 2007 in six 1-ha plots in a Sicilian citrus orchard under integrated pest management. A total of 180,000 A. melinus adults was released in each of three plots and the other plots were left as untreated control. The flight range of the parasitoid was evaluated, for 35 days after the release, on 16 trees per each plot, located at 20 and 40 m from the central release point using yellow sticky traps activated with Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae) sexual pheromone and by monitoring the percentage parasitism of the scale on fruits and twigs. The effects of the distance from the release point and density of susceptible stages of host on parasitoid dispersal were evaluated. The number of wasps captured during the whole trial was greater in the traps located 20 m from the release point than in those at 40 m and in the control plots. Aphytis melinus dispersed over distances less than 40 m based on both the lower percentage parasitism and numbers captured recorded at distances of 40 m. The results are discussed in the context of the biological control of California red scale in citrus orchards by means of wasp releases. In particular, the release points should be no more than 40 m apart for a quick and homogeneous colonization of the area treated.

Do Biopesticides Affect the Demographic Traits of a Parasitoid Wasp and Its Biocontrol Services through Sublethal Effects?

“…Bracon nigricans is widespread in the Palaearctic area and it attacks various Lepidopteran species [33], including T. absoluta in Europe [34], [35]. Parasitoids are organisms that have evolved a wide spectrum of fine and specialized physiological and behavioral mechanisms to locate, attack, and develop on their hosts 36–40. Braconid wasps are key natural enemies of several insect pests within a broad range of cropping systems worldwide [34], [41].…”

Life stage-dependent susceptibility of Aphytis melinus DeBach (Hymenoptera: Aphelinidae) to two pesticides commonly used in citrus orchards

“…The effectiveness of Aphytis spp. in the scale control could depend on many agro-ecological factors, such as the fitness of the released insects (Vasquez and Morse, 2012), their field dispersal capacity (Zappalà et al, 2012), the availability of the susceptible host instars and their size (Luck and Podoler, 1985), the interaction with other natural enemies (Heimpel et al, 1997a;Borer et al, 2003;Vanaclocha et al, 2013a), and the presence in the tree canopy of insecticide residues (Suma et al, 2009;Garcerá et al, 2013;Vanaclocha et al, 2013b).…”

Interaction between ants and the Mediterranean fruit fly: New insights for biological control

“…The environmental impact resulting from the wide use of insecticides has led to initiatives directed at reducing reliance on chemical control Qu et al, 2015), such as releasing biological control agents, as has happened for other key pests such as Aonidiella aurantii Maskell (Hemiptera: Diaspididae) (Zappalà et al, 2012) and mealybugs. Several ant species are known to prey on C. capitata: Pheidole megacephala (Fabricius), Linepithema humile (Mayr) and Solenopsis geminata (Fabricius) are well reported examples.…”