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Zinnia elegans
Nematodes: Two species of nematodes infest this host: Meloidogyne incognita, which causes root knot; and Aphelenchoides ritzema-bosi, which causes angular spots on the leaves. For control see sections in this book dealing with nematodes. Consult ...More…
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ZINNIA INSECT PROBLEMS
Michigan State University Extension — Aphids suck plant juices and can be controlled with Four-lined plant bug causes small, round, brown sunken Mites cause the foliage to lose its green color and spots on the leaves. become bronzed or stippled. dusts or sprays.More…
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ZINNIA DISEASE PROBLEMS
Michigan State University Extension — Blight starts as reddish brown spots with graying centers. Dark brown cankers form on the stems and flowers are Powdery mildew is found on zinnia, particularly late in Bacterial leaf spot causes reddish brown, angular spots on No chemical control ...More…
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VIOLA INSECT PROBLEMS
Michigan State University Extension — Aphids suck plant juices and can be controlled with dust Cutworms eat the foliage. Violet gall midge larva attacks the leaves at the Greenhouse leaf tier webs the flower buds and leaves Violet sawfly larvae skeletonize the leaves and then ...More…
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VINCA DISEASE PROBLEMS
Michigan State University Extension — Blight causes brown or black spots which extend inward Space plants farther apart in subsequent plantings. Remove infected plants. Canker and dieback cause the shoot tip to become dark Several fungi cause leaf spots on periwinkle. Root rots cause ...More…
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VERBENA INSECT PROBLEMS
Michigan State University Extension — Aphids suck plant juices but are easily controlled with Verbena leaf miner makes blotches along the leaf margins Greenhouse whitefly infests and feeds on verbena causing Thrips rasp the leaf tissue then suck the plant juices. Mites cause bronzing ...More…
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VERBENA DISEASE PROBLEMS
Michigan State University Extension — Bacterial wilt causes leaves to turn yellow and the plants Severe infections will turn the leaves yellow. to wilt and die, often without blooming. leaves. Shaded plants will be more severely infected.More…
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Stokesia laevis--Stokes Aster
Michigan State University Extension — Flowers: Blue, white Comments: Stokes Aster produces 4-inch flowers in summer. Give the plant full sun and a well-drained soil. The Propagation: Propagate by seed or by division done in the Farm 1999, Lake County Nursery 1997, Wayside Gardens ...More…
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Ipheion uniflorum--Spring Starflower
Michigan State University Extension — Height: 6 in Spacing: 8 in Flowers: White, blue Comments: Spring Starflower is native to South America. It produces white flower in the spring. The plant will Propagation: The bulbs may be lifted and separated. In References for Cultivars: White ...More…
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Snapdragon Diseases
Plant Pathology at Penn — Definite yellow spots form on leaves and stems. These turn white and have a brown border. Leaves die as do entire plants if stems are girdled. Heat and ventilate to maintain low humidity. Water in a manner that keeps foliage surfaces dry. Apply ...More…
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Petunia Diseases
Plant Pathology at Penn — Maintain low relative humidity. Apply fludioxonil, chlorothalonil, fenhexamid, mancozeb, or a mixture of the two to protect plants. Branches wilt and the plant rapidly dies as the crown. Young plants are quickly killed. Outdoors if the weather is ...More…
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Viola spp.--Pansy
Michigan State University Extension — Height: 12 in Spacing: 10 in Flowers: Blue, orange, purple, red, white, yellow Comments: Pansy is a biennial grown as an annual. There Pansy performs best during the cool days of spring and Fertilize during the growing season. Young ...More…