Parasitic Wasp of Whtefly
Like Encarsia formosa, Eretmocerus eremicus is a parasitic wasp for whitefly control. Eretmocerus can develop in any larval stage of the whitefly, but it prefers the second and early third stage. Eretmocerus eremicus lays its eggs under the whitefly larva. After 3 days the translucent eggs turn brown. If an egg is laid in the first larval stage, a development rest occurs, Eretmocerus larvae will not develop before the whitefly larva has reached the second larval stage.
The complete life cycle takes 17 to 20 days, depending on temperature and the larval stage of whitefly. Two weeks after parasitation, the pupa will turn yellow, not black as is the case for Encarsia. In order to leave its host, Eretmocerusmakes a small round hole in the parasitised whitefly, just as Encarsia. Both males and females are lemon-coloured. The males are only dark yellow on the upperside of the thorax, a part of their underside is brown.
Eretmocerus is Encarsia formosa’s welcome assistant in whitefly control because of the following advantages:
- If the whitefly population is big (high insect pressure), Eretmocerus will perform more host feeding.
- At high temperatures, Eretmocerus eremicus lives longer than Encarsia, and works better.
- E. eremicus better withstands pesticides than Encarsia, which is important in integrated production systems.
- Both greenhouse whitefly and sweetpotato whitefly can be parasitised by Eretmocerus eremicus.
- Parasitised pupae are very easy to recognize due to their yellow colour.