Diagnosing For Dummies. ~Marie S. Rojas

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1 Diagnosing For Dummies ~Marie S. Rojas

2 Integrated Pest Management - IPM An effective and environmentally sensitive system of pest management that relies on a combination of practices.

3 When using an IPM approach, ALL control options are considered cultural, chemical and biological. Often, landscape plants can defend themselves from pests if the plants are given proper care. Under optimal conditions, most pests have parasites, predators or pathogens that keep their populations below serious damage levels. Unfortunately, urban landscapes (homeowners!) frequently cause plant stress, requiring intervention to reduce pest attack. Using an integrated approach that stresses plant health care and low impact pesticides will help boost the plant s own defenses and conserve biological controls.

4 IPM: Fact vs. Fiction Fiction: Organic pesticides are more safe for people, animals, and the environment. Fact: Many organic pesticides are known rodent carcinogens, can kill worms, bees or other beneficials and/or persist in the soil.

Acute Toxicity of Botanical Insecticides to A. mellifera Adult workers and worker larvae experienced significantly different mortality rates across the dietary insecticide treatments.

7 Acute Toxicity of Botanical Insecticides to A. mellifera Adult workers and worker larvae experienced significantly different mortality rates across the dietary insecticide treatments. Adult workers that ingested citronella oil, eucalyptus oil, garlic extract, neem oil, or rotenone suffered from 42% to 60% higher mortality rates than workers fed with uncontaminated control diets. Only the andiroba oil did not increase the adult worker mortality. Worker larvae exposed to dietary andiroba oil, garlic extract, and neem oil experienced an increased mortality compared with workers fed on control diets. In contrast, the citronella oil, eucalyptus oil, and rotenone showed no significant acute toxicity on worker bee larvae (Fig. 1). Mortality (means ± SE) of A. mellifera adult workers (72 h botanical insecticide exposure) and larvae (dietary botanical insecticide exposure). Vânia M. Xavier et al. J Insect Sci 2015;15:137 The Author Published by Oxford University Press on behalf of the Entomological Society of America.

8 Organic Pesticides Not Always 'Greener' Choice, Study Finds ScienceDaily (June 23, 2010) Consumers shouldn't assume that because a product is organic, it's also environmentally friendly. A University of Guelph study reveals some organic pesticides can have a higher environmental impact than conventional pesticides because the organic product may require larger doses. Compared to the synthetic pesticides, the mineral oil-based and fungal products were less effective, as they also killed ladybugs and flower bugs, which are important regulators of aphid population and growth. In terms of making pest management decisions and trying to do what is best for the environment, it's important to look at every compound and make a selection based on the environmental impact quotient rather than if it's simply natural or synthetic. It's a simplification that just doesn't work when it comes to minimizing environmental impact.

9 Integrated Pest Management Benefits Use comprehensive information on the life cycles of pests and their interaction with plants. Combine this information with available pest control methods. Manage pest damage with the least possible hazard to people, property, and the environment. When working with homeowners don t squander those educational opportunities!

10 The Doctor Is In Just like a physician, do a full examination/work up. Ask lots of questions. Approach the problem with an open mind - don t jump to conclusions. Samples should be large, with both healthy and damaged tissue evident. Don t look for trouble. Most problems will be pretty common. Don t have homeowner mentality. Often (especially with diseases) by the time a problem is noticed, it is too late to control. Other times, beneficials may be able to take care of the problem, if given time.

11 The Four W s What, When, Where, Why WHAT: What species of plant? Cannot move forward without knowing! Many problems are plant-specific. Example: Lilac=? Hemlock=? Familiarize yourself with key plant key pest associations.

12 The Four W s What, When, Where, Why WHEN: Think about the time of year you are seeing the problem. Majority of problems (insect, disease, abiotic) are driven by climatic factors: temperature, rainfall, season. Don t forget past weather conditions! The previous year s droughty summer, an unusually warm/cold winter, that cool/wet spring any could give clues as to what the problem is.

13 The Four W s What, When, Where, Why WHERE: (There are several Wheres to ask): Where is the plant located? Often, site factors have a LOT to do with the plant problem. Azaleas sited in full sun =? Dwarf Alberta spruce in a planter beside door=? Also note where the damage/problem is on the plant: Is the problem only on one side of the plant or all over? Are the newly-emerging leaves affected or only older leaves? Is the damage on the upper leaf surface or lower? Is it only on the stem?

14 The Four W s What, When, Where, Why WHY: Once you have answered all of the questions, you should have a pretty good idea why the plant is experiencing a problem, what the problem is, and what to do about it.

The location of the feeding leaves, stems, bark, can

15 Insect Pest Identification Mouthparts and feeding damage can aid in pest identification/control. The location of the feeding leaves, stems, bark, can also give clues to what kind of insect is damaging the plant.

16 Chewing Insects Bite off chunks of food. Skeletonizing: eat all the way through the leaf, leaving some tiny veins intact. Older caterpillars, most sawfly larva, Japanese beetles.

17 Chewing Insects Defoliation: when either most or all of the leaf is consumed. Mature caterpillars or large adult beetles. Usually indicates large populations.

18 Chewing Insects Window feeding : insect chews through one leaf surface and consumes the interior of the leaf, leaving the other surface intact. Leaf beetles, young caterpillars (bagworms).

19 Chewing Insects - Borers Tunneling/boring: insects tunnel into plant material. Moth caterpillars include lilac borer, pine moth, peachtree borer, squash vine borer. Beetles include ambrosia, bronze birch borer, flatheaded appletree borer.

20 Tunneling Chewers (Borers) Flatheaded appletree borer

21 Ambrosia Beetle

22 Chewing Insects - Leafminers Specialized borers. Female lays eggs on leaf surface. Eggs hatch, bore into leaf and feed in between leaf surfaces. Leafminers are larvae of flies, wasps, moths, or beetles. Mines can be serpentine (columbine leafminer), blotch (boxwood leafminer), or a combination (holly leafminer).

23 Leafminers Locust leafminer Columbine leafminer

In response to the damage or chemical substance, the plant tissue grows around

24 Gall Makers Certain kinds of flies, wasps, psyllids, and mites. Females lay eggs on plant tissue (leaf, stem, buds). In response to the damage or chemical substance, the plant tissue grows around the egg, enclosing the insect. The insect feeds/develops inside the swelling. Usually not harmful to the plant, just unsightly.

25 Sucking Insects Mouthparts are shaped like elongated tubes that stab into the plant or animal and suck the juices. Examples include: aphids, scales, mealybugs, leafhoppers, plant bugs, thrips, and mites.

Some feed on newly expanding leaves causing them to become distorted, twisted and

26 Sucking Insects Leaf Feeders Pierce the surface of the leaf and suck out green tissue, causing the leaf to look dotted (stippling). Some feed on newly expanding leaves causing them to become distorted, twisted and curled. Thrips and aphids usually do this. Sometimes leaf feeders transmit viruses via sucking potato leafhopper.

27 Cryptomeria Scale Stippling damage Fern Scale Leaf distortion Aphid Aphid

28 Sucking Insects Bark Feeders Felted Scale Some scales, adelgids, spittlebugs, and treehoppers feed through the bark of stems, twigs and trunks, causing dieback. Japanese Maple Scale

29 Sucking Insects Some sucking insects (certain scales, aphids and planthoppers) exude a sticky substance, called honeydew, while feeding. A black mold grows on the honeydew (sooty mold). If you see ants, shiny sticky goo, or black stuff on plants (or cars, walks, etc.) look up!

30 Plant Diseases Plants can contract diseases from fungi, bacteria and viruses. Diseases are much harder to diagnose. Often, abiotic problems mimic disease symptoms. Frequently environmentally driven. Most are very hard to cure or control, so prevention is the best way to manage. Disease-resistant varieties, placement (don t crowd!), and watering practices go a long way toward minimizing stress and fostering healthy, disease-resistant plants.

31 Disease Diagnostics When trying to determine what is afflicting the plants, keep in mind: Diseases tend to start at a specific point on the plant and spread from there. Try to note the pattern of the problem in the landscape. Most pathogens are host-specific, so if the oak has anthracnose, it won t spread onto the dogwood. Similarly, if you are seeing a similar problem on a variety of plant species, it is probably NOT a disease! Diseases usually develop slowly, over time.

32 Fungi Fungal pathogens can cause: leaf spots, blights, wilting, galls, root rot, cankers, and fruit rot. Fungi are the most easily seen with the naked eye. Can observe: spores, rusts, and mycelium. Many grow best in dark, wet, shady, closely planted areas, when temperatures are between degrees F.

33 One Fungus Four Ways

34 Fungi In Landscape Volutella blight Azalea gall Powdery mildew Cedar apple rust gall on juniper Cedar apple rust on crabapple leaf

35 Bacteria Bacteria are microscopic and difficult to detect without lab equipment. Bacteria can cause leaf spots, blights, cankers, wilting, oozing, soft rot, and galls. Can be present, but inactive in a plant until environmental conditions are favorable.

36 Bacteria In The Landscape Fire blight Crown gall Fire blight

37 Bacteria In The Landscape Bacterial leaf scorch

38 Viruses Viruses are submicroscopic. Once inside, they cause the plant to reproduce more virus particles. Infected plants often appear distorted or stunted, have odd color patterns (rings, mottling) or necrotic spots on the leaves, yellow appearance (chlorosis), or have abnormal flower coloration/formation. Often transmitted via insects (aphids, leafhoppers, thrips), vegetative propagation, or sap (can contaminate hands/tools).

39 How Viruses Look In Plants U of IL E Wilt (Verticillium) Distortion (Rose rosette) Unusual color patterns Mottling (Rose mosaic)

40 Cultural (Abiotic) Factors Many plant problems are not due to insect or disease pests. In fact, many pest and disease problems in the landscape can be traced back to some initial cultural problem. Proper plant selection and care is an important part of an integrated landscape management program.

41 What Happened To My Tree??

42 Don t forget their feet!! Crown dieback may have soil-based causes!

wind. Roots were cut to reduce risk of girdling of main stem.

44 One of my favorite pictures. Great example of a container grown plant. Roots are wrapped around in circle. Without correction, these plants have the potential to blow over in wind. Roots were cut to reduce risk of girdling of main stem. These roots are starting to circle around tree and should be removed. Same tree after removal of circling roots Report excerpt courtesy Complete Plant Healthcare, Inc.

45 When wire baskets are left on they can girdle the flare of trees, especially on fast growing plants like Crape Myrtles. The basket is cut but not dug out of the roots. Report excerpt courtesy Complete Plant Healthcare, Inc.

46 Improper mulching can be problematic. Too much mulch may: Suffocate plant roots and/or cause roots to grow into the mulch near the surface. Create a crust that impedes water infiltration. Entice borers and voles. Lead to soil ph problems.

48 Horticultural Homicide!

50 CSI: Horticulture

51 Practice Troubleshooting Where is the damage? What kind of plant? What time of year?

53 Practice Troubleshooting What species of plant and how many affected? What time of year are you seeing the problem? What have past weather conditions been?

54 Cherry trees after an early cold snap.

55 Practice Troubleshooting What type of plant? Where are you seeing the problem? What time of year are you seeing the damage?

56 Nandina exhibiting winter injury.

57 Practice Troubleshoot What type of plant? Where are you seeing the problem? CLUE: Why is she wearing mittens?

58 Cold injury on Cercidiphyllum japonicum

59 Practice Troubleshooting What type of plant? Where are you seeing the problem? What time of year are you seeing the damage?

60 Practice Troubleshooting What type of plant? Where are you seeing the problem? Any other clues?

61 Exhaust damage from equipment.

62 Diagnostic Resources Penn State Woody Ornamental Insect, Mite, and Disease Management: IPMNET: UMD/Maryland Extension site with weekly reports of pest/disease problems scouts are seeing in the landscape. Managing Insects and Mites on Woody Plants: an IPM Approach. John A. Davidson and Michael J. Raupp, Tree Care Industry Association. Diseases of Trees and Shrubs. Sinclair, Lyon, and Johnson, Cornell University Press. Insects That Feed on Trees and Shrubs. Johnson and Lyon, Cornell University Press. IPM For Gardeners A guide to Integrated Pest Management. Raymond A. Cloyd, Philip L. Nixon, Nancy R. Pataky, Timber Press. Garden Insects of North America. Whitney Crenshaw, Princeton University Press, Second Edition. Manual of Woody Landscape Plants. Michael A. Dirr, Stipes Publishing.

Pest Management in Vegetable Gardens. Pam Brown Extension Agent Emeritus, Gardening Coach Pampered Gardeners, LLC

Pest Management in Vegetable Gardens Pam Brown Extension Agent Emeritus, Gardening Coach Pampered Gardeners, LLC pamperedgardeners@gmail.com Pest Management Involves: Providing proper cultural practices