Inherited Sterility inTuta absoluta(Lepidoptera: Gelechiidae): Pest Population Suppression and Potential for Combined Use with a Generalist Predator

Abstract

Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the most devastating pests of tomato. We studied whether partially sterile T. absoluta males and fully sterile females were capable of suppressing wild populations of this moth in semi-controlled conditions. After irradiating T. absoluta pupae with 200 Gy, emerged males and females were released at 10:1 (treated:untreated) and 15:1 over-flooding ratios inside field cages containing tomato plants. The number of eggs and larvae produced was recorded once per wk during 3 mo. An over-flooding ratio of 10:1 caused a decline in larvae production compared with the untreated control cages, but these differences were not statistically significant. Using an over-flooding ratio of 15:1, the moth population in the cages with irradiated insects decreased significantly compared with those in the untreated control cages. In addition, the possibility of combining inherited sterility and a natural enemy as a strategy to manage this pest was investigated. We studied in no choice and choice tests the predation behavior of females of the egg predator Tupiocoris cucurbitaceus (Hemiptera: Miridae) on eggs derived from the following parental T. absoluta crosses:  U ×  U (control),  U ×  I and  I ×  U (where U = untreated, I = irradiated). In the no choice test, females of the T. cucurbitaceus readily consumed T. absoluta eggs regardless of their origin. In the choice test, T. cucurbitaceus females consumed similar numbers of eggs of untreated parents and eggs oviposited from crosses in which the male had been irradiated. However, the mirid females preyed on significantly more eggs-roughly 20% more-from irradiated females than on eggs from untreated females. We conclude that it is possible to achieve a certain level of suppression of a T. absoluta wild population through the release of irradiated insects, and that it is technically feasible to combine the use of the predator T. cucurbitaceus with inherited sterility to control this moth pest.

Overview of Technological Advances Toward Greater Efficiency and Efficacy in Sterile Insect-Inherited Sterility Programs Against Moth Pests

“…Adult emergence of the tomato leaf miner decreased with increasing X ray doses that had been applied to pupae, but these treatments did not affect the longevities of irradiated P adult males and F 1 adult males, nor was the sex ratio affected by them. A dose of 200 Gy completely sterilized females of T. absoluta (Cagnotti et al 2012(Cagnotti et al , 2016, in this special issue).…”

The tomato leafminer (Tuta absoluta) (Lepidoptera: Gelechiidae) attack in Nigeria: effect of climate change on over-sighted pest or agro-bioterrorism?

“…Releases of irradiated and sterile males (Cagnotti et al, 2016) are also being developed as an eco-friendly management option. Biological control using entomopathogenic fungal species, particularly the anamorphs of Hypocreales, Metarhizium anisopliae has been reported (Contreras et al, 2014).…”

Advances and Challenges of Using the Sterile Insect Technique for the Management of Pest Lepidoptera

“…The radiation sensitivity of female moths appeared species-dependent, i.e., female codling moths were completely sterile when treated with a dose of 100 Gy [113], whereas a dose of 150 Gy was sufficient to completely sterilize females of E. saccharina and the European grape vine moth Lobesia botrana (Denis and Schiffermüller) (Tortricidae) [114,115]. Females of the litchi stem-end borer Conopomorpha sinensis Bradley (Gracillariidae) and the tomato leaf miner T. absoluta (Gelechiidae) were more radioresistant, and required 200 Gy for complete sterility [116,117,118], whereas eggs produced by females of the light brown apple moth (LBAM) Epiphyas postvittana (Walker) (Lymantriidae), which had been irradiated with 250 Gy, still showed 0.1% hatch [119]. A dose of 300 Gy was required to fully sterilize females of the date moth, Ectomyelois ceratoniae (Zeller) (Pyralidae) [120].…”

“…A substerilizing dose of 250 Gy administered to C. sinensis males would be adequate for programs that include an IS component based on competitiveness values obtained in field cages [118]. Releasing substerile T. absoluta males in field cages at a 15:1 substerile (200 Gy-treated pupae) to untreated male ratio caused a significant decline in larval production as compared with that in untreated control cages [117]. The radiation dose and mating frequency of LBAM was significantly negatively correlated [129], and the production of the sex pheromone by the females declined significantly with increasing doses of radiation.…”