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Plant NameTypeDescription 
Damping-offCantaloupe, MelonsDiseaseMelon seeds and seedlings may be attacked by a fungus in the soil. Seeds may be rotted and seedlings may be infected and fail to emerge from the soil. Emerged seedlings are also attacked, causing them to wilt and topple over. Water-soaked or brownish lesions are often visible on the stem at the soil line. Plants become more resistant to attack as they mature. Damping-off fungi are more of a problem in cold soils with poor drainage, and in conjunction with overwatering.
Powdery mildewCantaloupe, MelonsDiseasePowdery mildew is a common fungal disease of melons. Upper and lower leaf surfaces and stems are typically affected. Small white spots quickly enlarge into patches of characteristic powdery-white fungal growth. Older leaves, shaded leaves, and leaf undersides are the favored locations for powdery mildew development, but it can quickly spread to involve large portions of the plant. Tiny, speck-like, black fungal structures may be present in the white mats. Severely affected leaves may yellow and drop prematurely. Fruit quality can be affected and yield is reduced. Disease development is favored by humid weather, cool nights, and cloudy days. Dense plantings are more likely to be affected. The fungus can overwinter on diseased vines.
Verticillium wiltCantaloupe, MelonsDiseaseVerticillium wilt is caused by a fungus which can persist in the soil for many years. It has a broad host range, including many vegetables (potato and tomato are favored hosts), woody and herbaceous ornamentals, fruit trees, and weeds. Typically, the fungus attacks the roots and moves throughout the plant via the vascular system. Symptoms may not be noticed until plants are stressed. Leaves wilt and develop yellow, V-shaped areas along the margins. Affected leaves die. The wilt progresses upward through the plant and may kill entire vines. Discoloration of the vascular system is noticeable when cuts are made into stems near the base of the plant. Cool soil temperatures favor disease development.
Brown marmorated stink bugCantaloupe, MelonsInsectThe brown marmorated stink bug (BMSB) is an introduced pest species from Asia that is spreading quickly across the United States. Nymphs and adults feed on a wide variety of plant hosts. BMSB prefers to feed on fruit, seeds, and seed pods, but will also feed on stems and leaves of some hosts. Both adults and nymphs have piercing-sucking mouthparts and inject digestive enzymes into plant tissues to aid in feeding. BMSB damage appears initially as a pinprick surrounded by a discolored spot on the surface of the fruit. These injured areas may turn yellow or decay as the fruit matures, or entire fruits may become distorted or catfaced. The surface spots often appear slightly sunken as whitish corky or spongy areas develop under the skin. Secondary damage from rot may occur at the feeding site and severely damaged fruits may rot on the vine. Other known vegetable hosts of BMSB include tomato, pepper, corn, bean, and cucumber. One or two generations of BMSB per year are expected in the Pacific Northwest. Adults overwinter in sheltered locations (including houses, where they can become a significant nuisance pest). In the spring, light green to white eggs are laid in groups of about 20 to 30 on the underside of leaves. Young stink bugs, or nymphs, are black with a red-and-black striped abdomen. Nymphs often feed in groups when young. Older nymphs are dark with white bands on body, legs, and antennae. They may feed in groups or singly. Adults are a little over 1/2 inch long, with a shield-shaped body. Body color on adults is mottled gray and brown, while the legs and antennae have alternating dark and light bands. The abdomen also has dark and light bands which are visible at the edge of the wings. NOTE: BMSB adults closely resemble other stink bugs found in WA and OR. For more information on BMSB identification, see FS079E, Pest Watch: Brown Marmorated Stink Bug, available at
Spider mitesCantaloupe, MelonsInsectSpider mites are tiny, eight-legged mites which may range in color from yellowish to green or red. They typically feed on the underside of leaves, causing a yellowish to bronze stippling or speckling of leaves. Severe infestations can cause entire leaves to turn yellow and die, which may result in reduced yield. Spider mite feeding is usually accompanied by webbing on the underside of leaves. The mites may be visible as "moving dust" in the webbing. Mite infestations are worse in hot, dry, dusty conditions.
Squash bugCantaloupe, MelonsInsectThe squash bug attacks squash, pumpkin, melons, and related crops. Adults are typically dark brown, but may have gray or light brown markings. They are about 3/4" long at maturity. Brown to reddish eggs are laid along the veins of new leaves. The newly hatched nymphs (immature bugs) are greenish to gray. Squash bug nymphs and adults feed on the leaves, causing small yellow specks which later turn brown. Squash bugs also inject a toxin into vines which can cause a wilt from the point of attack to the end of the vine. Affected runners wilt and turn black and crisp. Small plants may be killed, while larger plants may lose several runners. Squash bugs may also attack young fruit. Adult squash bugs overwinter in debris and sheltered places in the garden.