Extension Horticulture Help Desk Training

Transcription

1 Extension Horticulture Help Desk Training 7/17/13 Seasonal problems Buckmoth caterpillar Belongs to group Giant Silkworm caterpillars 2 long brown to purplishblack with numerous yellow spots. reddish spines that may have red or black tips. on oak or willow from spring to mid summer. Single generation per year Found in the Purcell Rd. area of PWC 1

2 Puss caterpillar slug like caterpillar poisonous spines Short & stocky creeps on leaves in a slug like manner. head & legs not visible typically, one generation per year grown larvae found in the late summer. Saddleback caterpillar brown in front and rear, green in the middle purple spot in center of the green saddle prominent horns on Stings by this insect can cause severe irritation. typically found on deciduous trees: basswood, chestnut, cherry, oak, and plum, occasionally found on corn. 2

3 How to Avoid stings Most encounters with stinging caterpillars result from accidently brushing against leaves on which they are feeding. The chances of running into these insects are relatively low, but occasionally one species may be very abundant. The more time spent in wooded areas, the greater the opportunity for contact. Most of these caterpillars are distinctly marked or brightly colored. If you find one on yourself, don't brush it off or slap it with a bare hand. Use a stick or other object to remove it carefully. Hollow spines may break off in clothing or gloves. First Aid for Stings No really effective home first aid treatments for caterpillar stings are available. Adhesive tape or transparent tape may be used to pull out some of the broken spines in the sting area. Washing the area thoroughly with soap and water may help remove some of the irritating venom. Prompt application of an ice pack or baking soda may help to reduce pain and prevent swelling. Antihistaminic drugs, often administered for bee and wasp stings, are reportedly ineffective. See a physician if severe reactions occur. Very young, aged or persons in poor health are more likely to suffer severe reaction symptoms 3

4 Mites Two spotted spider mites, southern red mites, spruce spider mite Look for fine, yellow stippling damage on foliage. mites usually found on the undersides of the leaves. Monitor by placing a piece of light colored paper on a clip board and tap the branches over the paper. Look for the mites with 10x lens Walnut Twig Beetle/Thousand Cankers Disease Disease complex Walnut twig beetle vectors Geosmithia morbida Geosmithia infects plant tissues in larval galleries, coalesce and kills Confirmed in Occoquan PWC is quarantined Yellowing leaves Top down dieback Death within 3 years No cure 4

5 Southern Blight Caused by fungus Sclerotium rolfsii Also called crown rot or white mold Wide host range Prevention is best strategy. Easily transported. Sanitation, clean tools, hands, shoes No effective fungicide Sclerotia Cicada Killer Wasps 1 ½ rusty head & thorax, with black/rusty yellow band markings on abdomin. Dig underground burrows in loose soil Paralyzed cicadas will be food for their larvae Females have stingers which they plunge into cicadas to inject venom that paralyzes them. However, they are not aggressive and do not have nest guarding instinct of honey bees and hornets. You can walk through areas where they are active without attracting attention Males lack stingers but are territorial. They may hover and challenge trespassers but are harmless. May disrupt plants roots. If a few plants are affected, drench the area around their nest with water & they may abandon site 5

6 Rose Rosette Disease Eriophyid mite, Phyllocoptes spreads viral pathogen. Witches brooms or distorted, clustering of small branches Red pigmentation, although red pigmentation is not a consistent symptom Canes have excessive growth of soft, pliable red or green thorns. No effective control Remove invasive multiflora roses Early detection & removal of infected plants Correct spacing of rose bushes critical so mites cannot travel easily Effective control of mites with certain miticides can reduce the risk of spread. Must be used with cultural controls Mushrooms and other fungi Some mushrooms grow in, and form their fruiting structures on living trees causing decay of the sapwood or of the heartwood. Many woodland mushrooms are essential to good growth, and even survival of trees & establish a relationship (mycorrhizal) with roots of living trees that is mutually beneficial. Armillaria root rot 6

7 Scales General rules Identify plant and the type of scale Treat when insects susceptible crawler stage Weeds See Thomas new handout 7

8 Anthracnose It s not just for Spring anymore! Spring, summer and fall! Cicadas 20 eggs laid at a time in each inch long slit, over 600 eggs! End of the branch will often die and break partially off, so it hangs down and the leaves turn brown. flagging prune Eggs hatch in 2 months, and nymphs drop to ground & look for plant roots 8

9 This disease is favored by wet Septoria weather and temperatures of 72 Vegetables, flowers, 79 F. woody species (maple, Use resistant cultivars. Remove and dogwood, poplar) destroy infected leaves. Use 1 2 Annuals first, sunken, year rotations. Stake annuals for black flecks. Lesions better air circulation. Keep irrigation develop into circular water off of leaves. Sulfur spots with tan centers applications during warm wet and dark margins. On weather may reduce infection. woody species spots Rake and destroy infected leaves in coalesce to form dead the fall. blotches. Septoria overwinters on dead leaves and in twigs infected previous season. Early blight Common on tomatoes, potatoes, eggplant Fungus overwinters in soil and plant debris Can also be transmitted on seed and transplants Typically splashed by rainfall on lower leaves Bulls eye pattern of concentric rings Moves to stems and fruitsdark lesions Can spread in wet or dry weather, but favored by rainfall and heavy dew Select resistant varieties No overhead watering Select resistant varieties 9

10 Beetles Damage Symptoms Heavy infestations result in turf dying in irregular patches. Birds, skunks, raccoons and opossums commonly dig up turf around the dead patches. Moles may tunnel extensively where grub populations are high. Infested turf feels spongy under foot and is easily lifted because of the absence of roots. The adults do not feed on ornamental plants or turf. White Grubs and Lawn Problems 10