Rhododendums Being Eaten Question ?

[Robert11]

Hi,

Have some nice Rhodendums that have come into bloom lately, and look like they are being eaten (but hard to tell for sure)..

Live outside of Boston, and have Deer and Wild Turkeys in my area.

Are either of these known "eaters" of Rhododendums ?

Thanks, Bob

[Frank]

Deer eat mine. I've fenced with netting to protect it. Turkeys eat berries and bugs.

[Stephen Henning]

Hi Bob,

Leaves chewed on edges is a symptom of chewing insects. Most are nocturnal feeders and can be found at night with a flashlight. The most prominent chewing insects on rhododendrons and azaleas are the Black Vine Weevil, Otiorhynchus sulcatus, Strawberry Root Weevil, Otiorhynchus ovatus, or Twobanded Japanese Weevil, Callirhopalus bifasciatus. Adult weevils feed on the leaves at night except the Twobanded Japanese Weevil which feed during the day. Specimens may be collected during the day or at night for identification depending upon the weevil. The major damage is caused by weevil larvae which girdle the roots and kill the plant. Larvacidal drenches may be used to kill them but are of limited effectiveness. Foliar sprays are very effective at controlling adult weevils when leaf notching starts. Foliar sprays must be repeated until no adults emerge. Twobanded Japanese weevils are apparently resistant to carbaryl (Sevin), diazinon, and malathion. Orthene gives good control when applied as a foliar spray and drench. Since weevils can't fly and spend part of each day in the soil and part of each day feeding, you can paint the trunks with Tanglefoot to stop them, but make sure no branches are touching the ground.

If the leaves are being ripped off, then it is deer. They are especially bad in winter, but can be a problem all year long in areas where they have developed a taste for rhododendrons.

Entire leaves being eaten by caterpillars is an indication of an infestation of caterpillars such as the Red-headed Azalea Caterpillar, Datana major. These caterpillars are black with rows of white or pale yellow spots, reddish brown legs, head and neck area and are 2 1/2 inches when mature. Preferred host plants are azaleas, but they may also attack witch hazel, sumac, apple, red oak and andromeda. The caterpillars feed together when young and disperse as they mature. Branches or entire plants may be defoliated. Damage occurs in late summer and fall. Look for caterpillars when defoliation damage occurs, and if only a few caterpillars are present, pick them off by hand. If needed, spray shrubs with B.t. (Bacillus thuringiensis ), a microbial insecticide that is specific for caterpillars. It is sold under various trade names including Caterpillar Attack, Thuricide, Dipel, etc. Apply sprays when caterpillars are numerous and less than 3/4 of an inch long. Larger caterpillars must be sprayed with a registered residual insecticide such as carbaryl (Sevin 50WP) or cyfluthrin (Bayer Advanced Garden Multi-Insect Killer).

Leaves with crescent shaped holes. The Cranberry Rootworm, Rhadopterus picipes, chews holes in the leaf, some of which are crescent shaped.

Other chewing insects include caterpillars, leaf rollers, sawflies (moth larvae), cut worms, and loopers. The larvae of several species of insects can cause damage as the result of chewing on new foliage. These pests hatch as the new growth is forming, and often eat out large areas of the soft growth. They may also roll the leaf with a white web. Damage only occurs on soft growth. To control, use Orthene, Malathion, or Diazinon.

Chewed flowers and new leaves can be a sign of slugs and snails. These pests feed on soft new growth and on flowers. To control, use Metaldehyde baits or sprays

Hope this helps.

[Robert11]

Hi,

Just a quick thanks for all the great info. Appreciate it.

Bob