Tetrastischus howardi density and dispersal toward augmentation biological control of sugarcane borer

Abstract

The number of Tetrastischus howardi (Olliff) females to be released and their dispersion should be known, that way, used D. saccharalis pupae as sentinel host to measure parasitism as function of the release density of the parasitoid and its location in the field. Two sets of trials were run aiming first to define the number of parasitoids to be released and the dispersal of the parasitoid using plots in sugarcane commercial fields, respectively. Pieces of sugarcane stalk holding sentinel pupae were taken to the field and exposed to parasitism in both trials. The parasitoid was released at the rate of 20, 40, 80, and 160 females per sentinel pupa, except for the control plot without releasing. The parasitism rate was calculated based on the recovered pupae after 96 h of exposure time from releasing the parasitoids. The models estimated the best parasitism rate by releasing 102 parasitoids per pupa. In the second trial, sentinel pupae were arranged in five subsequent circles corresponding 4, 8, 12, 16, and 20 m around the central parasitoid releasing point at rate of 4, 8, 12, 16, and 18 pupae per circle. The mean estimated dispersal distance was 7.64 m, with a covering area of 80.07 m 2 . Based on these findings, release of T. howardi is recommended in 125 points per hectare of sugarcane at rate of 102 females per pupa of the pest aiming to achieve homogeneous distribution and parasitism.

Percepción De Los Agricultores Sobre La Eficacia De Parasitoides en El Control De Plagas Y en La Sostenibilidad Agroecológica Del Limonero, Riochico, Portoviejo, Ecuador

“…Los parasitoides como medios de control de plagas son individuos que se alimentan de un huésped de la misma clase taxonómica siendo su fase activa el e s t (Du et al, 2018;Barbosa et al, 2019).…”

Parasitism rate of Plutella xylostella (Lepidoptera: Plutellidae) larvae in greenhouse by Tetrastichus howardi (Hymenoptera: Eulophidae) females at different densities

“…The natural biological control is an alternative with reports of parasitoid and predator species on P. xylostella in Brassicaceae crops (Karindah et al, 2005;Dancau et al, 2019). In biological control programs which use parasitoid insects, hymenoptera stand out for their wide diversity (Silva et al, 2020) Using mass breeding techniques, evaluating their biological parameters and the release of these parasitoids (Barbosa et al, 2019;Ongaratto et al, 2020).…”

“…Studies on the female densities are necessary to increase the efficiency of natural enemies in pest control (Scheiner and Martin, 2020). The best density of parasitoid females to host individuals is important to estimate the number of insects released and that of releasing points of natural enemies in biological control programs (Barbosa et al, 2019).…”

Do fall armyworm’s Metaflumizone resistante populations affect the activity of Trichogramma pretiosum?

“…Nevertheless, for this natural enemy to be effectively used, its activity, behavior, and efficiency must be understood (Barbosa et al, 2019) in its host. It is known that females of these parasitoids have strategies that facilitate identification of a quality host through surface contact of antennas (Bento and Nardi, 2012).…”