COOLEY SPRUCE GALL ADELGID

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1 Problem Pests of Trees/Shrubs Problem Pests Workshop 2017 Cooley Spruce Gall Adelgid Cankers Physiol/Enviro Damage + Browning of Evergreens Gall formers Black Knot Bronze Leaf Disease Yellow headed Spruce Sawfly Nest forming Caterpillars Outline Disease / Life cycle Symptoms Conditions Favouring Disease / Insect Development Management Strategies COOLEY SPRUCE GALL ADELGID Spruce Gall Adelgid Several species Adelges cooleyi (Cooley spruce gall adelgid) Adelges lariciatus (Spruce gall adelgid) Adelges strobilobius (Pale spruce gall adelgid) Depends on region Crops Affected = spruce trees Life Cycle Aphid like insects 2 year life cycle Some species alternate between hosts Coolley spruce gall adelgid (CSPA) alternates between Douglas fir and Spruce Other species (e.g. A. lariciatus or A. strobilobius) may alternate between Larch/Tamarack and Spruce 1

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3 Symptoms The appearance of galls varies with the pest species and the age of the gall Early galls of the CSPA typically 4 6 cm (2 3 inches) in length Early galls of other species are typically shorter (approx cm or 1 inch) in length and resemble a pineapple Galls of other species may have a portion of the stem extending beyond the gall Galls may be more frequent on shaded sides of trees Early gall Very old gall Older gall 3

4 Management The application of registered chemical controls must be very specific in terms of timing, in order to target nymphs prior to entering galls Removal of galls will not provide control Infestations tend to be very cyclic, with populations controlled or reduced naturally over time Nest forming caterpillars Several different types will show up NEST FORMING CATERPILLARS Tend to be seasonally cyclic or have definite patterns 4

5 UGLY NEST CATERPILLAR Chokecherry planting with a problem Many nests visible Nest full of debris Nest full of debris note pupal casings, leaves, frass, webbing, etc. Nests full of debris 5

6 Management? Sprays would have to be timed precisely to catch adults prior to egg laying or catch early larvae prior to nest formation Biological controls should work Remove and destroy nests Adult moth FOREST TENT CATERPILLAR Forest Tent Caterpillar larva Management? Remove and destroy nests Apply appropriate and registered products Bacillus thuringiensis (Bt) products are highly effective Pest outbreaks are very cyclic and fairly predicatable Early grouping of young caterpillars 6

7 PINE FALSE WEBWORM Gross!!! Photo by Lorraine Taylor Mass of debris containing pest Pine false webworm adult Photo by Lorraine Taylor Eggs laid on needles Photo by Lorraine Taylor 7

8 Management? Controls would have to be applied to catch the adults, prior to egg laying and nest formation NOTE NOT ALL CRAWLING WORMY THINGS ARE CATERPILLARS (SO DON T MANAGE THEM LIKE THEY ARE) YELLOW HEADED SPRUCE SAWFLY Evidence of feeding Evidence of feeding Evidence of feeding note needle stubs (and culprit stage right) 8

9 Culprit(s) Yellow headed spruce sawfly Management? Apply treatment to control larvae 9

10 Physiological / Environmental Damage PHYSIOLOGICAL / ENVIRONMENTAL DAMAGE Can manifest in many ways Discolouration Wilting Distortion Plant decline / death Etc. Needle droop 10

11 BROWNING OF EVERGREENS Browning can be the symptom of a wide range of issues Moisture issues (too little or too much) Herbicide injury Salts Diseases Insect attack Other symptoms may be associated with browning It's important to note: Patterns Scope Top or bottom Needle damage Etc. 11

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13 Management? Difficult May treat specific issues if identified properly Ensure trees have adequate everything (nutrients, moisture, drainage, air flow, etc.) 13

14 Apiosporina morbosa Black Knot BLACK KNOT Affects all plants within the genus Prunus, including various species of cherries (chokecherry, Nanking cherry, pin cherry, sand cherry, sour cherry, etc.), plums, almond, etc. Disease Cycle Ascospores are produced on mature galls in the spring, infecting growing points The disease will develop internally and externally Galls will grow in size each year, producing spores annually Plant structure is affected and branch strength may be reduced Eventually, plants may die A single infected tree or bush can infect a wide area Management Remove sources of inoculum in adjacent areas Prune out infected branches during the dormant season, when plants are dormant and galls are highly visible Galls should be pruned out, with cuts being made at least 6 inches beyond obviously infected materials Pruning cuts should be made to an appropriate point (healthy collar, etc.) If possible, pruning tools may be disinfected between cuts, however this may be difficult or impractical in many situations 14

15 Management Destroy infected material by burning, burial and/or proper composting, or removal from the site Ensure plants are healthy and free from stress Ensure adequate canopy ventilation Chemical controls are limited, fairly ineffective and expensive Consider hiring a certified arborist for complex pruning activities BRONZE LEAF DISEASE Apioplagiostoma populi Affects: Swedish Columnar Aspen, tower poplar, poplar hybrid clones 15

16 Management No chemicals are registered for the management of this disease Avoid planting highly susceptible types in areas where disease is present Sanitation is the main management practice Remove and destroy fallen leaves Prune off infected branches back to healthy wood in the case of most susceptible poplar and aspen hybrids, this means back to the trunk Management Avoid planting trees species too close together This improves air flow and reduces leaf debris accumulation Increased density will increase humidity and potential ease of spore transfer Canopy density should also be kept open, to allow good air movement Remove infected trees Avoid propagating from infected material Ensure plants have sufficient light, moisture and nutrients Cankers There are a wide range of different species that cause cankers CANKERS Typically described as sunken/depressed areas on the branches or trunks May be associated with weeping, discolouration or other symptoms 16

17 Cytospora canker on Saskatoon berry Cytospora canker on spruce (Photo by fctreecare.com) Nectria canker on maple (Photo by missouriabotanicalgarden.org) USDA Forest Service Region 8 Southern, USDA Forest Service, Bugwood.org Linda Haugen, USDA Forest Service, Bugwood.org 17

18 GALL FORMING / DEFORMING INSECTS POPLAR BUD GALL MITE (ACERIA PARAPOPULI) WILLOW RED GALL SAWFLY (PONTANIA PROXIMA) CYPNID WASP GALLS 18

19 WILLOW PINE CONE GALL MIDGE 19

20 APHIDS APHIDS 20

21 WOOLY ELM APHID / WOOLY APPLE APHID 21

22 OTHER EXAMPLES QUESTIONS??? Rob Spencer, BSA, MSc, P.Ag. Commercial Horticulture Specialist Alberta Ag Info Centre 310 FARM 22