The side‐effects of pesticides on the egg parasitoid Trichogramma cacoeciae Marchal (Hym., Trichogrammatidae), acute dose‐response and persistence tests

Abstract

The side-effects of 21 pesticides were tested on the Hymenoptera egg parasitoid Trichogramma cacoeciae, using four different types of laboratory methods. The methods combined: (a) adult parasitoid exposure to fresh pesticide residue on glass plates ~ initial toxicity worse case to select harmless preparations, (b) direct spray of host eggs enclosing the parasitoid pupae (less susceptible life stage), (c) duration of harmful activity (persistence) on adultsselect preparations that are less persistent and (d) dose-response exposures LD,, -to assess the risk margin. The results showed that the preparations (used at the highest recommended dose) greatly differed in their initial toxicity as well as in their persistence. The fungicide Topsin M@ (thiophanat-methyl) and the herbicides Pyramin@ (chloridazon), Butisan' S (metazachlor) and Banvel" 70 WG (dicamba) were harmless to T. cacoeciae. The insecticides Match" (lufenuron) and Admirals, (pyriproxifen), the fungicides Bavistin" (carbendazim), AlietteE (fosetyl) and Captan" 83 W (captan) as well as the herbicides Duplosan% 600 KV (mecoprop-p) and Focuss; (cycloxydim) were slightly harmful. The fungicide Scala@ (pyrimethanil) was moderately harmful. TeImion% (rape oil), Vertimec@ (abamectin) and Scala were harmful in the initial toxicity test but only slightly persistent. These less persistent preparations are likely to have less impact on the natural enemy in the field. In the persistence test, Zolone Flow@ (phosalon), Polo@ (difenthiuron), Euparen@ M (tolylfluanid), Dithane@ M 45 (mancozeb), KumulusLR, (sulphur) constantly reduced parasitism by between 90 and 100% and were rated as persistent. The direct spray of parasitized host eggs showed that Zolone Flow, Polo, Eupareum M, Dithane M 45, Scala and Touchdown" were harmless to the parasitoid pupae within the egg, that Telmion, Thiram@ 80 WG and Kumulus were slightly harmful and Vertimec was moderately harmful. The dose-response test indicated a risk quotient (dose in g or ml product per ha/LDSo value) of spray drift for off-field parasitoids for the chemicals in the order of increasing risk as follows: Polo (1.33) followed by Thiram (3.62), Touchdown (7.54), Scala (10.39), Dithane M 45 (13.94), Telmion (27.04) and Zolone Flow (39.34).

Seletividade de produtos fitossanitários utilizados na cultura do pessegueiro a Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae)

“…Resultados similares foram relatados por Giolo et al (2005a) para captana na mesma concentração testada no presente trabalho, com T. pretiosum. Por outro lado, Hassan et al (1998) obtiveram 49,10% de redução no parasitismo por T. cacoeciae, com o uso de captana 83 W, que foi enquadrado na classe 2 (levemente nocivo). As diferenças obtidas neste caso, provavelmente devem-se à concentração de ingrediente ativo de 5,68 vezes superior à que foi testada no presente estudo.…”

Susceptibilidade de adultos de Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) a fungicidas utilizados no controle de doenças da macieira

“…De forma similar ao observado no experimento I, Hassan (1994) também obteve para T. cacoeciae a classe 1 com captana (Orthocid 83). No entanto, Hassan et al (1998) obtiveram 49,1% de redução no parasitismo de T. cacoeciae, obtendo a classe 2 para este mesmo ingrediente ativo captana (Captan 83 W). As variações nos resultados provavelmente se devem aos diferentes produtos comerciais usados em diferentes doses e formulações, demonstrando assim a importância sempre da caracterização do pesticida pela sua marca comercial e das características intrínsecas de cada um.…”

Toxicity of organic supplies for the egg parasitoid Telenomus podisi

“…Overall, the present research has shown that the tested organic treatments are compatible for use in combination with the parasitoid preservation in organic pest management. Even chlorpyrifos was less noxious to T. podisi as compared to other egg parasitoids as Trichogramma pretiosum (BUENO et al, 2008) and T. cacoeciae (HASSAN et al, 1998), for example. It did not reduce adult emergence from sprayed pupae.…”