Introduction
The wasp Opius dissitus Muesebeck is a solitary, larva-pupal, Hymenopteran endoparasitoid of Liriomyza leafminers. Several studies report that O. dissitus were reared from Liriomyza (Diptera: Agromyzidae) leafminers infesting plant leaves of celery, tomato, potato, beans, etc. (unpublished data, Li et al.; Stegmaier 1972).
Distribution
Opius dissitus is reported from Africa, Asia, Europe, and North America (Bordat et al. 1995a; Petcharat et al. 2002; Stegmaier 1972; Neuenschwander 1987).
Description and Life Cycle
Adults: The adult O. dissitus are black in color. The antennae are black and thin, and almost the same length as their body.
Eggs: Opius dissitus females lay their eggs directly inside the late stage Liriomyza larvae bodies. The average size of the egg is about 0.28 mm (Bordat et al. 1995a).
Larvae: The O. dissitus larvae develop inside the Liriomyza leafminer larvae. However, the parasitized leafminer larvae still consume the tissue of plant leaves until their pupation. The O. dissitus larvae develop through two instars inside the leafminer larvae (Bordat et al. 1995a), and eventually kill the leafminer in the pupal stage. The mature O. dissitus larvae then pupate inside the leafminer pupae. The optimal temperature for O. dissitus development on host of L. trifolii is reported as 25°C–30°C (Bordat at al. 1995b).
Pupae: Opius dissitus early stage pupae are yellow and have red eyes, while the mature stage pupae are black in color. Opius dissitus adults emerge out of the leafminer pupae. One adult emerges from a single parasitized pupa (unpublished data Li et al.)
Credit: Jian Li, UF/IFAS
Credit: Jian Li, UF/IFAS
Credit: Jian Li, UF/IFAS
Hosts
In Florida, Opius dissitus larvae were found and collected, then reared to adults, from the leaves of several crops infested by Liriomyza leafminers (Stegmaier 1972; Schuster and Wharton 1993). Important Liriomyza economic pest species include the pea leafminer, L. huidobrensis (Blanchard); the vegetable leafminer, L. sativae Blanchard; and the American serpentine leafminer, L. trifolii (Burgess).
Economic Importance
Opius dissitus is a potential biological control agent for Liriomyza leafminers on vegetable and ornamental plants. Opius dissitus was found to be the most abundant parasitoid (63% of all the parasitoids) of L. trifolii on snap bean crops in south Florida, and the seasonal density of O. dissitus had a similar pattern with L. trifolii (unpublished data Li et al.). Opius dissitus was also found to be one of the major hymenopteran parasitoids of Liriomyza leafminer on tomato crops (Schuster and Wharton 1993). Petitt (2004) reported that O. dissitus was reared and released to control Liriomyza leafminers at the Walt Disney World Resort.
Selected References
Bordat D. 1995a. "Morphometric, biological and behavioral differences between (Hym., Eulophidae) and (Hym., Braconidae) parasitoids of (Dipt., Agromyzidae)." Journal of Applied Entomology 119: 423–427.
Bordat D. 1995b. "Influence of temperature on (Hym., Braconidae), a parasitoid of (Dipt: Agromyzidae)." Entomophaga 40: 119–124.
Neuenschwander P. 1987. "Introduction of exotic parasitic wasps for the control of (Diptera: Agromyzidae) in Senegal." Tropical Pest Management 33: 290–297.
Petcharat J. 2002. "Larval parasitoids of agromyzid leafminer genus in the southern Thailand: species and their host plants." Songklanakarin Journal of Scientific Technology 24: 467–472.
Petitt LF. 2004. "Rearing and release of (Hymenoptera: Braconidae) for biological control of leafminers at the Walt Disney World Resort. Symposium: Advances In Management For Agromyzid Leaf Miners." Entomological Society of America Annual Meeting and Exhibition.
Schuster DJ, Wharton RA. 1993. "Hymenopterous parasitoids of leaf-mining spp. (Diptera: Agromyzidae) on tomato in Florida." Environmental Entomology 22: 1188–1191.
Stegmaier CE. 1972. "Parasitic Hymenoptera bred from the family Agromyzidae (Diptera) with special reference to south Florida." Florida Entomologist 55: 273–282.
