by Nanette Londeree, Master Rosarian
SIGNS
- Adult flying insects with black and yellow bands on their abdomen
- Tiny whitish to gray oblong eggs, singly on their sides, usually near aphids or within aphid colonies
- Legless larvae 1/32 to 1/2 inch long, with a yellow longitudinal stripe on the back
- Pear-shaped, green to dark brown pupa found on plants or on the soil surface
SYMPTOMS
Honeybee looking insects hovering over flowers
CAUSE
- Syrphid or hover flies in the Syrphidae family
- 1000 species in North America, many being very abundant
OPTIMAL CONDITIONS / HABITAT
- Regularly found where aphids are present in agricultural, landscape, and garden habitats
- Adults feast on pollen and nectar – favorites include wild carrot and mustard, coriander, dill, fennel, sweet alyssum and yarrow
- Their movement from flower to flower makes them an important pollinator
- Usually most visible in the latter half of the growing season, after aphid infestations have been well established
TREATMENT
Prevention:
None – these insects should be encouraged with diverse plantings of nectar and pollen producing plants
Elimination:
None – you don’t want to eliminate these from the garden
GOOD GUY / BAD GUY?
A really good guy; the larvae are predators and the adult is a pollinator
Syrphid Fly photo by Jill Fromer, used with permission from:
http://www.istockphoto.com/