Can the parasitoid Necremnus tutae (Hymenoptera: Eulophidae) improve existing biological control of the tomato leafminer Tuta aboluta (Lepidoptera: Gelechiidae)?

Abstract

Necremnus tutae is native to the Mediterranean region where it has been observed in greenhouses parasitizing the invasive Tuta absoluta on tomato. The objective of the present study was to determine whether augmentative releases of N. tutae can improve existing biological control of T. absoluta based on predation by Nesidicoris tenuis. Two experiments were carried out, of which the first evaluated different N. tutae release rates (1 and 2 N. tutae m-2 week-1). The parasitoid reduced plant and fruit damage, especially at the higher rate. However, such reduction was considered insufficient given the large numbers of parasitoids needed and still unacceptable level of fruit damage. The second experiment focused on combining the most efficient rate of N. tutae of those evaluated during the first experiment, with the pre- and post-planting release of N. tenuis and supplemental additions of Ephestia kuehniella eggs. Addition of N. tutae decreased leaf damage by T. absoluta regardless the release method for N. tenuis, but the pre-plant release of N. tenuis alone was sufficient to prevent fruit damage by T. absoluta. This suggested that the addition of N. tutae may not be necessary to obtain satisfactory control of T. absoluta following pre-plant application of N. tenuis, although different options for using N. tutae in commercial crops may still be possible.

Survival of a specialist natural enemy experiencing resource competition with an omnivorous predator when sharing the invasive prey Tuta absoluta

“…In our experiment, when the two natural enemy species were together, there was twice as many as natural enemies as in the treatment with only one species. An additive effect of their two efficiencies explains the lowest level of the shared prey in this treatment and reveals that (i) the negative interactions between the two natural enemy species did not cancel the interest of having them together instead of choosing only one and (ii) the efficiency of one of the two natural enemies did not hide the efficiency of the other one, contrary to the results of Calvo, Soriano, Stansly, and Belda (2016) who tested different natural enemy species.…”

Seasonal variation in natural mortality factors of Tuta absoluta (Lepidoptera: Gelechiidae) in open‐field tomato cultivation

“…Although parasitoids action has not been the most important mortality factor, considering all the periods evaluated, they were present in all the periods, with greater expression in the fall and winter periods and in the 3rd‐ and 4th‐instar larval. Various predators and parasitoids have been reported naturally attacking T. absoluta in tomato crops in Europe and North Africa and more recently in India and South America (Biondi, Desneux, Amiens‐Desneux, Siscaro, & Zappalà, ; Calvo, Soriano, Stansly, & Belda, ). Some efforts have targeted the activity of the T. absoluta egg (Cabello et al., ; Chailleux et al., ; El‐Arnaouty et al., ; Martins et al., ) and larval parasitoids (Biondi et al., ; Chailleux, Desneux, Arnó, & Gabarra, ).…”

The potential ofDicyphus hesperusas a biological control agent of potato psyllid and sweetpotato whitefly in tomato

“…Treatment effects on B. tabaci , B. cockerelli , and D. hesperus were analyzed using linear mixed effects models ( α = 0.05), with time (weeks) as random factor nested in blocks (replicates) to correct for pseudoreplication due to repeated measures (see Messelink et al , 2008; Calvo et al , 2016 b ). Thereafter, treatments were compared, contingent on a significant model, through model simplification by combining treatments (Crawley, 2002).…”