Selected Defoliators

Question 1

Host and range of IDW

Answer 1

Climate change has been slowly increasing the range and severity of budworm outbreaks. More larva surviving winter.

Range: dry southern interior. IDF and south coast CDF

Host: Fd, (b, l, S)

Prefers: warm and dry Fd dominated dense stands with uneven age.

Question 2

How does WS budworm overwinter?

Answer 2

As a larva

Question 3

What age suffers the most from IDW

Answer 3

Younger trees up to intermediate are most likely to die

Older trees suffer reduced growth

Question 4

Why is spruce budworm the most damaging defoliator?

Answer 4

Outbreaks on average from 5-9 years but have been as long as 25 years with fluctuations in weather.

Dominants reduced growth for 2-3 years after defoliation at 50%.

Question 5

Insect ID

Answer 5

Insect eggs: scales on needles

Larva: naked, greenish brown. 4 white spots per segment. Dark head.

Adult too many look alikes

Question 6

Signs on tree

Answer 6

Bud mining (frass around buds)

Webbing at tips of branch (protection)

burnt red appearance appearing in a band across the landscape there the elevation was just right: universal to all defoliation and quick death of needles. Tree is not necessarily dead

Question 7

What is the dif between IDW and IDT damage**

Answer 7

IDT: kill concentrated at top of tree. Patch kill landscape pattern

IDW: kill concentrated around all buds. Landscape level bands

Question 8

IDW

Answer 8

Insect defoliator worm - western spruce budworm