CATS Southwest Pest and Disease 3 — Questions and Answers
Question 1: Which insect is primarily responsible for the decline of piñon-juniper woodlands across the Southwest during prolonged drought periods?
- Western pine beetle (Dendroctonus brevicomis)
- Piñon ips (Ips confusus) (Correct answer)
- Pine sawyer (Monochamus sp.)
- Pales weevil (Hylobius pales)
Correct answer: Piñon ips (Ips confusus)
Piñon ips (Ips confusus) has been the primary driver of mass piñon mortality during Southwest drought events, killing millions of trees.
Question 2: Bacterial wetwood (slime flux) seeping from a cottonwood trunk in Albuquerque is best managed by:
- Drilling relief holes and inserting drain pipes
- Improving tree vigor through appropriate irrigation and fertilization; avoid wounding (Correct answer)
- Applying systemic antibiotics as trunk injections
- Removing all affected bark with a chisel
Correct answer: Improving tree vigor through appropriate irrigation and fertilization; avoid wounding
Bacterial wetwood has no cure; management focuses on reducing tree stress through proper cultural practices while avoiding unnecessary wounding that introduces bacteria.
Question 3: A certified arborist notices galls on the roots of a young Arizona cypress. The most likely causal organism is:
- Crown gall (Agrobacterium tumefaciens) (Correct answer)
- Phytophthora cinnamomi
- Armillaria mellea
- Verticillium dahliae
Correct answer: Crown gall (Agrobacterium tumefaciens)
Crown gall caused by Agrobacterium tumefaciens produces characteristic warty, tumor-like growths at the root crown and on roots of many woody plants.
Question 4: The cottonwood borer (Plectrodera scalator) is most effectively detected during its adult stage by:
- Setting pheromone traps in spring
- Inspecting trunks and root flares for large black-and-white adult beetles in summer (Correct answer)
- Sampling soil for larvae in winter
- Using sticky band traps on trunks
Correct answer: Inspecting trunks and root flares for large black-and-white adult beetles in summer
Adult cottonwood borers are large, distinctive black-and-white beetles that can be visually detected on trunk bases and roots during summer emergence.
Question 5: Seiridium canker on Italian cypress and other Cupressus species in the Southwest is most accurately described as:
- A bacterial blight spread by aphids
- A fungal disease causing dieback of branches with resinous cankers on affected stems (Correct answer)
- A viral mosaic disease spread by leafhoppers
- A root rot disease favored by dry soils
Correct answer: A fungal disease causing dieback of branches with resinous cankers on affected stems
Seiridium canker (Seiridium cardinale and related species) is a fungal disease causing branch dieback and resin-soaked cankers, particularly severe on stressed cypress.
Question 6: Which abiotic condition mimics the symptoms of nitrogen deficiency in urban trees planted in Albuquerque's alkaline soils?
- Manganese toxicity
- Iron chlorosis due to high soil pH limiting iron availability (Correct answer)
- Boron deficiency
- Sodium toxicity from road salt
Correct answer: Iron chlorosis due to high soil pH limiting iron availability
Alkaline soils above pH 7.5 lock up iron, causing interveinal chlorosis (yellowing between green veins) that resembles nutrient deficiency.
Question 7: Apache pine tip moth (Rhyacionia sp.) infestations on young ponderosa pines in the Sandia Mountains are best managed using which integrated approach?
- Annual soil fumigation around the root zone
- Pruning and destroying infested terminals combined with appropriately timed insecticide applications (Correct answer)
- Releasing parasitic wasps alone as biological control
- Wrapping trunks with burlap to prevent adult oviposition
Correct answer: Pruning and destroying infested terminals combined with appropriately timed insecticide applications
Removing and destroying infested shoot tips combined with systemic or contact insecticides timed to new adult emergence provides the most effective control.
CATS Southwest Pest and Disease 3
Which insect is primarily responsible for the decline of piñon-juniper woodlands across the Southwest during prolonged drought periods?