Eggs are approximately 0.7 millimeters in diameter, with a smooth, shiny surface. They are white when first deposited but become brown as they age.

BLACK VINE WEEVIL LARVAE
Photo courtesy of Dr. Jim Baker, North Carolina State University

Biology: The black vine weevil was first recognized as a pest of grapes in Germany in 1934. The beetle was found in Connecticut in 1910 and has since become a serious ornamental pest. Many herbaceous and woody plants have been listed as hosts for the black vine weevil including, hemlock, rhododendron, and yew.

Larvae can stunt the growth of a plant by feeding on the roots. Larger roots are stripped of their bark or girdled, or they have notches chewed out of them. The adult weevils chew the edges of the leaves, the tips of needles, or devour entire needles. Older foliage is preferred to terminal growth.

Black vine weevils overwinter as mature larvae or as pupae. However, a few adults also survive the winter to feed and deposit eggs during a second season. This weevil is parthenogenetic, meaning females have the ability to reproduce without the assistance of males. Each female deposits an average of 200 eggs.

BLACK VINE WEEVIL DAMAGE
Photo courtesy of Dr. Jim Baker, North Carolina State University

Adults feed at night and drop from the plant, feigning death when disturbed. These weevils cannot fly, so they must crawl or be carried to uninfested areas.

Control: The current North Carolina Agricultural Chemicals Manual contains information about specific chemical controls.

DAMAGE CAUSED BY RHODODENDRON BORER
Photo courtesy of Dr. Ray Kriner, Rutgers University

Description: The rhododendron borer moth has a black head with green and white markings. The thorax is black and blue with a broad patch of pale yellow or shiny white on each side. The abdomen is also black and blue with segments two, four, and five trimmed with yellow dorsally; legs are yellow and white apically and dark with some light color markings basally. The wings are transparent with a rusty-black fringe and some yellow scales. There is a tuft of black and yellow scales at the tope of the abdomen. The female has broader bands on segments two, four, and five than the male does. The female's anal tuft is short and rounded, whereas the male's is fan shaped. The moth has a wingspan of 10 to 15 millimeters. Larvae are yellow-white caterpillars approximately 13 millimeters long.

Biology: The rhododendron borer is indigenous to the United States and is found wherever rhododendron grows abundantly. Rhododendron is the principal host for the rhododendron borer. Mountain laurel and azalea are also attacked.

Twigs and small branches are preferred by the rhododendron borer. Infested branches become weakened and may break off. Leaves on infested branches often turn brown. Occasionally older parts of the shrubs are attached. The main truck may have numerous holes with fine sawdust protruding from them. Past infestations on older plant parts will appear as shallow, longitudinal grooves in the bark.

Adults emerge from their pupation sites during May and June and deposit eggs on twigs. Newly hatched larvae bore into stems and dig long tunnels in the soft pith. The tunnels become filled with small, reddish fecal pellets and serve as sites for overwintering and spring pupation.

Control: Pruning infested branches helps to control the rhododendron borer. For specific chemical controls consult the current North Carolina Agricultural Chemicals Manual.

RHODODENDRON LACE BUG ADULT
Photo courtesy of Dr. Jim Baker, North Carolina State University

Description: The small adult, about 3.5 millimeters long and 2.4 millimeters wide, has lacy wings that are unusually broad. It is pale yellow with yellowish legs and antennae.

The yellowish-white egg is 0.4 millimeters long and 0.2 millimeters wide. Basically cylindrical, it is tapered at both ends, with the neck bent to one side. The eggs are deposited in irregular rows, usually along the larger veins. Their caps are level with the leaf surface. The females deposit a brown substance over the eggs, which hardens to form a varnish-like covering.

Unlike most lace bugs, the rhododendron lace bug has only four nymphal stages. The nymphs feed in groups in the younger stages. They range from 0.9 to 2.1 millimeters in length are black and spiny.

Biology: The rhododendron lace bug was originally described in the United States. The earliest report of the insect was from Pennsylvania, and the pest is now considered indigenous to the United States.

The pest attacks more than 120 types of rhododendrons, as well as mountain laurel and fetter-bush.

DAMAGE CAUSED BY RHODODENDRON LACE BUG
Photo courtesy of Dr. Jim Baker, North Carolina State University

Rhododendron lace bugs overwinter as eggs which hatch in April in Washington, DC area. There are only four nymphal stages, which require about 30 days for development.

The eggs are usually laid in new leaves along the midvein or a short distance from it. As many as 170 eggs can be found on a single leaf. Non-overwintering eggs hatch in about 3 weeks. The insect seems to favor relatively well-lighted sites, but bushes in the shade can also be badly infested. The pests are commonly transported in the egg stage on nursery stock.

Control: Rhododendron should be treated when the lace bugs are first notices. For specific chemical controls, the current North Carolina Agricultural Chemicals Manual should be consulted.

RHODODENDRON TIP MIDGE LARVA
Photo courtesy of Dr. Jim Baker, North Carolina State University

Description: The rhododendron tip midge is a light brown, 1-1/4 millimeter long fly. The hairy male has antennae 1-1/2 times the length of its body. The female, on the other hand, has a short ovipositor and antennae about as long as its body. Larva is a whitish, flattened maggot about 1.27 millimeters long. The egg and pupa have not been described.

Biology: This midge was first described in 1939 and has been reported in New York, New Jersey, Pennsylvania, and North Carolina.

Rhododendron is the only known host of this pest.

Maggots feed exclusively on tender, new growth. Young, infested leaves, usually less than 5 centimeters long, develop inwardly-rolled margins with swollen, greenish-yellow tissue. The margins may fold over the midrib. Lightly infested leaves have pale green bulges over most of the surface and become stunted and distorted. On severely infested plants, new growth may be so distorted after emergence that additional foliage fails to develop.

These pests overwinter as pupae in the soil. The adult flies emerge and lay eggs in the spring as new plant growth develops. The newly hatched larvae protect themselves by feeding from within the curled leaf margins. When mature, the maggots drop to the soil to pupate. Damage first appears in late May or early June and often reappears in August on the second flush of growth. Therefore, it seems that at least two generations occur each year.

Control: Heavy infestations of this pest are unusual and sporadic. An effective cultural control method is the removal and destruction of newly infested foliage. This practice may eliminate an infestation within a single year or two. No chemicals are currently registered for control of this pest.

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