Quiz

Posted by on Oct 31, 2011 in | Comments Off

Have you figured out what is on the leaf?

 

The Woolly Gall Wasp.

Gall wasps are very small and all but a few species are less than 5mm (1/4 inch) in length. There is a high degree of color variation between species. Some are black, others are red, yellow or amber. The larvae are legless and both larvae and pupae are white in color.

 

Galls occur on a wide variety of woody plants. There are many organisms that may cause gall formation including fungi, bacteria, nematodes or mites, but insects are the prime cause. Gall-forming insects include aphids, phylloxerans, psyllids, midges (gall gnats) and cynipid wasps (gall wasps). Each gall-forming insect produces a gall that is characteristic of that particular insect. Some galls may be as much as 50mm (2 inches) in diameter while others are so small they are rarely noticed.

 

The gall wasps are the most important insects that induce plant galls. Galls primarily occur on trees. A few occur on woody ornamental shrubs and flowers and they are virtually non-existent on bedding and foliage plants. Galls are found most commonly on the stems and leaves but also occur on trunks, flowers, leaf-shoot terminals, petioles and roots. They occur in a wide range of colors and shapes. They may occur as spheres to tubes with a surface that may be smooth, hairy or even covered with spines. Gall production itself is believed to result from the reaction of cambium and other meristematic tissues to stimuli produced by the larvae to cause the abnormal growths.

If you find a Woolly Gall Wasp on your trees or shrubs call us right away.