Insects on a Mimosa Tree

Identification

• The mimosa webworm (Homadaula anisocentra) produces larvae that spin gray webs around the mimosa tree and feed on the foliage. The eggs of the pest are tiny and white, turning pink just before hatching. The larvae themselves are gray or brown and adorned with five white stripes along their body. Upon pupation, a yellowish-brown insect develops inside a silken cocoon, before giving way to an adult silver or gray moth. Although rarely seen, it has wings and is covered with black dots.

Feeding Process

• The larvae overwinter in cocoons and can be discovered under bark along the trunk or in leaf litter on the ground. Hatching occurs in mid-June and the larvae pupate in late July, producing a second generation ready for overwintering. The larvae spin webs around the leaves of the mimosa and skeleton the foliage. Damage will begin to appear most severe late in the summer as the second generation of the mimosa webworm comes to life.

Control

• Management includes closely observing a mimosa tree for infestation and the pruning away of afflicted branches. Leaves that provide a nesting place for the insect in the winter should be raked away in the fall and destroyed. Insecticide should be applied in early June when the webs first appear, with a second application in August as the second generation of mimosa webworm larvae begin to make their presence known. Young, newly hatched larvae are most susceptible to the insecticide.

Cottony Cushion Scale

• Cottony cushion scale (Icerya purchasi) also makes a home in the mimosa tree, reports the University of Florida Institute of Food and Agricultural Sciences. This scale can be brown, yellow or orange and carries about its back a white, cottony egg sac containing between 600 and 800 eggs. Amazingly, the sac often becomes two to three times the size of the female scale itself. These scale suck away sap from all sections of the tree and can kill twigs and small branches and defoliate the tree.