163 Plant Problem Sunflower Moth Sunflower Aster Yellows Aster Leafhopper, Angular Leaf Spot Caterpillar Checkerspot Powdery Mildew Septoria Leaf Spot Aphids Rust November 21–30 stems November 11–20 roots November 1–10 October 21–31 October 11–20 October 1–10 crown September 21–30 September 11–20 September 1–10 trunk August 21–31 August 11–20 August 1–10 leaves leaves July 21–31 July 11–20 July 1–10 June 21–30 June 11–20 branches June 1–10 May 21–31 May 11–20 flower May 1–10 April 21–30 fruit April 11–20 April 1–10 March 21–31 KEY: March 11–20 Coneflower, Rudbeckia Coneflower, 10 March 1– Pest Damage on Pest ©The Board of Regents of the University of Nebraska–Lincoln. All rights reserved. All rights Nebraska–Lincoln. of University of the ©The of Regents Board Coneflower, Rudbeckia Plant Problem Signs/Symptoms Treatment Sunflower Moth Flowers at the peak of bloom Treat flowers with a microbial develop brown, powdery insecticide just after they open centers with fine webbing and thereafter as needed. Remove on them. Breaking apart the and destroy older infested heads center reveals a small, white- to help reduce local sunflower and-brown-striped caterpillar moth populations. feeding on developing seeds. Aster Yellows Plants are stunted with short internodes and have yellow foliage. Many secondary Remove infected plants. Apply shoots, sometimes growing insecticide to control insect on one side of the plant. vectors (leafhoppers). Flowers are greenish, deformed or absent. Leafhopper, Aster Regularly treat plants, beginning Small, greenish to tan, wedge in May and through the season, shaped, sucking pest; the with insecticidal sprays or systemic disease causes leaf-flecking. insecticides to control adults and This pest transmits aster yellows nymphs. Immediately remove plants disease, which causes yellowed, expressing aster yellows disease. distorted, and stunted growth. Keep plantings weed-free to reduce contact with alternate hosts. Angular Leaf Spot Angular, brown to purplish spots which cover the entire Sanitation. Avoid overhead leaf; spot may have a water- watering. Plant resistant varieties. soaked appearance. Checkerspot Caterpillar Larvae of a few species of beautiful Leaves have skeletonized checkerspot and crescent butterflies patches caused by clusters of feed on sunflower-related plants. black, fuzzy caterpillars feeding Damage usually is localized and on them. Later, caterpillars are minimal. Rather than kill them, black and yellow with prickly re-locate them to wild sunflower spines; they consume entire leaves. plants in the vicinity. Chances of re-infestation are low. 164 ©The Board of Regents of the University of Nebraska–Lincoln. All rights reserved. Coneflower, Rudbeckia Plant Problem Signs/Symptoms Treatment Powdery Mildew Sanitation. Improve air circulation. White powdery growth appears Avoid planting in shady areas in the mainly on older leaves and the landscape. Apply foliar fungicides stem. Premature defoliation. at disease onset. Septoria Leaf Spot Sanitation. Improve air circulation. Avoid over-crowding and overhead Small, usually round, dark irrigation. Apply foliar fungicide brown spots which enlarge to when disease is first observed and 1/8 to 1/4 inch in diamter. repeat application according to label instructions. Aphids Treat when aphid numbers Small, glossy, soft-bodied are increasing and damage is aphids cluster on growing apparent. Monitor new growth stems. Depending on the for signs of re-colonization, and species, they may be greenish, re-treat if necessary. Appropriate brownish or a deep red. Feeding insecticides include insecticidal causes foliage to turn yellow, soap, horticultural oil, neem oil, or and stunts growth. contact or systemic insecticides. Rust Avoid planting Carex species (sedges) Bright orange-yellow spore which severe as an alternate host pustules on leaves and stems. near Rudbeckia plantings. 165 ©The Board of Regents of the University of Nebraska–Lincoln. All rights reserved..