Selection Of A Trichogramma Species (Hym., Trichogrammatidae) For The Biological Control Of The Potato Moth Phthorimaea Operculella (Lep., Gelechiidae) By Host-Parasitism Behavioral Study

Currently, the "potato tuberworm", Phthorimaea operculella, and the "Guatemalan potato moth", Tecia solanivora (Lep.: Gelechiidae) are the two pests of the greatest economic importance in Spanish potato crops. For this reason, the potential as biological control agent of two egg parasitoid species -Trichogramma achaeae and T. cacoeciae (Hym.: Trichogrammatidae)- of the pest species P. operculella has been studied, under laboratory conditions. Three groups of trials have been carried out: "non-choice" test, "choice" test, and study of parasitic behavior. In all the trials the eggs of the pest specie were compared with the rearing host of the parasitoids: Ephestia kuehniella. In the results, "no choice" test, T. achaeae parasitized significantly more eggs of both species than T. cacoeciae. Thus, total egg mortality in P. operculella was 92.78 +/- 13.47% by T. achaeae versus 70.88 +/- 15.11% by T. cacoeciae. In turn, in the "choice" test, it was found that adult females of both parasitoid species preferred P. operculella eggs (beta(2) = 0.58 +/- 0.10 y beta(2) = 0.61 +/- 0.17 para T. achaeae y T. cacoeciae, respectively). Finally, in the parasitic behavior test, it was found that T. cacoeciae showed significantly shorter host searching times and shorter host handling times than T. achaeae. Both Trichogramma species seem to be good candidates as biological control agents of P. operculella, which must be subsequently confirmed by field and warehouse trials.