Pests on Trees

1. Pests on Trees Stephani Sandoval Extension Forest Health Specialist NMSU

2. Pests Signs vs. Symptoms Deciduous Pests Conifer Pests Bark Beetle Disease Diagnosis Pesticides Prevention Outline

3. Pests, what are they? • Insects that have an end result of an undesirable or unacceptable affect on plants and trees and/or interferes with management objectives • Cause damage and decrease aesthetics • Stunt growth • Vector diseases • Tree mortality • Directly or indirectly

4. Why Pest Outbreaks Occur • Stress caused to plant: • Water availability – Light requirement • Temperature/climate – Nutrient balance • Continuous food source • Tree in non-native area • Stress of transplant • New enemies • Invasive insect species

5. Why Pest Outbreaks Occur • Higher tree densities increases risk of insect infestation and disease • Construction Damage • Wounds inflicted upon bole of tree • Soil compaction

6. How do they effect the forest? Remember they can be beneficial such as pollination, prey upon other insects, and encourage natural selection (reduce the weak).

7. Signs vs. Symptoms • Symptoms are visual response of the plant due to an attack of an organism or abiotic factor. • Leaf spots – Wilting – Discoloration • Stunting – Resin – Multiple leaders

8. Signs vs. Symptoms • Signs are the visual presence of some structure formed by the attacker on the plant. • Egg masses – Insects – Boring Holes – Boring dust – Spore – Fruiting bodies

9. Signs and Symptoms • Examine entire plant • Leaves/Needles: Normal size, discoloration, deformed, holes, bumps, etc. • Buds/Reproductive Buds: abnormal growth, falling prematurely, rotting • Branches and Trunk: holes, cankers, conks, physical damage, oozing sap, etc. • At the base of the tree: Roots showing, burlap or container around roots, enough room for roots to grow, accumulating evidence: boring dust, insect excretes, egg masses

10. Definitions Gall Conk Canker

11. Categorizing Insects (Pests) • By method of feeding • Chewing: Feed on plant tissue such as leaves, flowers, buds, and twigs • Sucking: Ingest plant juices by using a “beak” to break the surface of tissue • Boring: tunnel under the bark and feed on the trees phloem, heartwood or sapwood

12. Western forest tent caterpillar Feed on a variety of deciduous ornamentals, aspens and willows

13. Santa Fe Ski Basin • Varity of Biotic Factors of Control • Insect Parasites • Predaceous beetles and bugs • Moths • Birds • Nucleopolyhedrosis virus

14. Extreme Populations • Strip entire tree • Travel down the tree and across ground in search of new foliage • Can make roads slippery

15. Fall webworm

16. Pear Slugs • Introduced Sawfly • Feed on cherry, plum, and other stone fruit trees • Two generations year • Leaves turn brown • Usually little impact • Wash off with insecticidal soap

17. Two-tree generations a year Overwinter in homes Banding Introduced species Likely cause of elm defoliation Elm leaf beetle

18. Prefer boxelder seed pods Overwinters in homes Insecticidal soap Two generations a year Vacuum and house hold cleaners Boxelder bug

19. Aphids • High number in short period of time • Great deal of destruction to vegetation • Serious pests as well as vectors of several plant diseases

20. Piercing sucking mouthparts • Produce sticky honeydew excrete • Feed on pinion in late winter and ponderosa in spring to avoid enemies

21. Ladybird Beetle ↓ Honeydew excretes ↑ on branches

22. Tiger moth • Usually not a serious pest in forest conditions • Adults emerge in late July-August • One generation/year • Noticeable in late winter/early spring

23. Tiger Moth • Adults are colorful with irritating hairs • Feed during fall and winter during warm days • Retreat to tent for warmth • Webbing found at base of tree

24. Douglas-fir tussock moth

25. Young Larvae are blackish with long hairs • Later instars are very colorful • Hairs cab be irritating • Females Flightless • Movement by caterpillar

26. Many natural enemies Most controlling the nuclear polyhedrosis virus Egg mass formed on female cocoon About 300 white spherical eggs One generation year

27. Pine tip moth Nantucket Southwestern

28. Attacks terminal buds • Eggs laid on new shoots or terminal buds from March-June • Larvae feed short time on needle base • Bore into buds, laterals, and terminals and mines out the pith • Growth is hindered but seldom kills the tree

29. Pitch moth and bark moths

30. Spring Feeders Summer Feeders Conifer sawflies

31. Conifer sawflies • Females cut slits into needles to lay eggs • Gregarious feeders • Young larvae skeletonize needles • Older larvae consume entire needle

32. Wash off with a hose • Prune branches • Pick of by hand

33. Western Spruce Budworm • Most widely distributed and destructive defoliator of conifers in Western N.A. • Attack Douglas-fir (red fir), white fir, and spruce • Top kill, tree growth loss, and mortality in seedlings and saplings Pictures Provided by USDA Forest Service

34. Western Spruce Budworm • Feeding larvae from May through June • Mine or tunnel year-old needles, closed buds, newly developing vegetation, and reproductive buds • July moths emerge, reproduce and die • Larvae hatch in ~10 days, they don’t feed a second time but seek shelter for the winter Pictures Provided by USDA Forest Service

35. Western Spruce Budworm • Management: • Thin to a single story canopy (i.e. thin over-story and then thin from below) • Increase non-host species such as ponderosa pine • Natural enemies • Insect parasites • Small mammals • Birds

36. Cooley spruce gall adelgid

37. Overwinters as an immature female under bark scales near the terminal spruce twigs Early spring: Female develops into stem-mother. Deposits up to 350 eggs under her cottony mass. Eventually, a winged generation is produced and flies to spruce. Winged adults fly to DF. 1-2 weeks later: Eggs hatch and nymphs settle and feed at base of young needles. When nymphs nature, gall opens and nymphs crawl to needles and mature. Cone-like galls form around the nymphs.

38. ← Egg mass Gall →

40. Needle miners

41. Pinion Needle Miners

42. Spider mites

43. Piñon Needle Scale • Bean-shaped bumps • Attack one year old needle • Suck sap from needles

44. Piñon Needle Scale • Males emerge in fall and overwinter at base of tree • Female overwinters on the needle and emerges in spring • Eggs laid in Feb-March

45. Eggs are yellow Held together loosely by a white cottony webbing

46. Piñon Needle Scale • Eggs can be rinsed off with a hose • Must be meticulous about cleaning up debris after rinsing • Pesticides are available

47. Outline • Common bark beetles • Bark beetles attacking ponderosa pine in the Southwest • Other bark beetle species on conifers • Effects of bark beetles on forest conditions • Management of pine bark beetles

48. Common Southwestern Conifer Bark Beetle Generain Scolytidae Dendroctonus spp. –pine, spruce, Douglas-fir (6 – 8 common species) Ips spp. – pines and spruce (10 species) Scolytus spp. – true fir, young Doug-fir Dryocoetes spp. – true firs (subalpine & corkbark fir) Phloeosinus spp. – Juniper and cypress Pityophthorus spp. -Twig beetles – mainly pines and Douglas-fir ( Over 30 species in NM plus other twig beetle genera including Pityogenes, Pityotrichus)

49. Bark Beetles • Bark beetles belong to Order Coleoptera and Family Scolytidae (6,000+ worldwide) • Every conifer in Southwest has associated bark beetles (often > 1 species per host) • Beetles are small in size (< ¼ inch) • Host, size & shape, and egg galleries aid in identification of bark beetle species • All life stages found in cambium or bark • Most bark beetles introduce stain fungi

50. Adult Pupa Larva 0” 1/4” 1/2”