Parasitism rate of Myzus persicae (Sulzer) by Diaeretiella rapae (McIntosh) in the presence of an alternative, resistant host

Diversidad de parasitoides primarios y secundarios del pulgón Myzus persicae (Hemiptera, Aphididae) en el duraznero Prunus persica (Rosales, Rosaceae) en la provincia de Mendoza, Argentina

“…En este estudio, la tasa de parasitoidismo promedio entre ambos años varió en un rango de entre 4,37-34,98 %, dando un promedio de 19,67 %. Estudios realizados a laboratorio por Ferreira et al (2018) determinaron una tasa de parasitoidismo sobre M. persicae con variaciones de 4,5-62,2 %. Por su parte, Sampaio et al (2001) determinaron un parasitoidismo con variaciones de 38-62 % en densidades de M. persicae de 80-20 áfidos.…”

Effects of acetamiprid on Lipaphis pseudobrassicae (Hemiptera: Aphididae) resistant and susceptible to the parasitoid Diaeretiella rapae (Hymenoptera: Braconidae, Aphidiinae)

“…Nevertheless, it is important to mention that the mummification proves the susceptibility of the aphid, but the survival does not necessarily prove resistance, thus the parasitism of a great number of individuals is necessarily to prove the resistance of the clone. Daily observations were made for 10 days, evaluating the number of aphids reaching adulthood and remaining alive (resistant) and those that were soon after molting to adults transformed into mummies (susceptible) (Ferreira et al, 2018). Fourth instar nymphs were used because even susceptible aphids that are successfully parasitized by D. rapae at this developmental stage can reach adulthood and reproduce before dying and becoming mummies (Ferreira et al 2018).…”

“…Biological control plays an important role in Integrated Pest Management (IPM) programs, especially considering its low cost and general lack of synthetic chemicals (Parra & Coelho, 2019). The main natural enemy of aphids in Brassica crops is the parasitoid Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae, Aphidiinae) (Starý et al, 2007;Akhtar et al, 2010;Sampaio et al, 2017); however, the low parasitism rate of D. rapae in L. pseudobrassicae, both in the field and laboratory, suggests that the population of L. pseudobrassicae in Uberlândia-MG is formed mostly of clones resistant to this parasitoid (Oliveira et al, 2013;Sampaio et al, 2017;Ferreira et al, 2018).…”

“…The cause of such resistance in L. pseudobrassicae is still under investigation; however, association with secondary symbionts is a possibility, since aphids susceptible to the parasitoid have been obtained within the offspring of resistant aphids (Ferreira et al, 2018). The association of aphids with these symbionts can result in adaptive advantages, such as increased heat tolerance, the ability to use host plants that, without the symbionts, would not be suitable for aphid feeding, and resistance to parasitoids (Chen et al, 2000;Oliver et al, 2003;Tsuchida et al, 2002;Vorburger et al, 2013;Cayetano et al, 2014).…”

“…Studies have demonstrated that biological control of the aphid L. pseudobrassicae with the parasitoid D. rapae is currently not effective due to the aphid's resistance to the parasitoid (Oliveira et al, 2013;Sampaio et al, 2017;Ferreira et al, 2018). A number of chemical control options have been considered, particularly using neonicotinoids such as acetamiprid, since acetamiprid is a systemic insecticide, absorbed by the plant and translocated throughout the plant in the sap in lethal amounts to sapfeeding insects such as the aphids (Tomizawa & Casida, 2003;Faria, 2009).…”