Table 3.

Average (±SE) cumulative ambrosia beetle attacks on irrigated and nonirrigated tree bolts treated with permethrin at different times (8−10 or 22−24 d) before introducing ethanol to attract ambrosia beetles

		Spring 2018		Fall 2018
Permethrin spray timing (days before ethanol)	Irrigation	Average (±SE) total attacks/ tree bolt	Total attacks	Average (±SE) total attacks/ tree bolt	Total attacks
Control	No	6.25 ± 0.63a	25	15.75 ± 3.28a	63
22–24	Yes	2.75 ± 0.63b	11	4.50 ± 0.65b	18
22–24	No	3.25 ± 1.25b	13	2.25 ± 0.85bc	9
8–10	Yes	3.00 ± 1.35b	12	0.25 ± 0.25c	1
8–10	No	1.75 ± 0.85b	7	1.25 ± 0.95bc	5

Different letters in the last column represent significant differences among permethrin spray timing treatments in total cumulative attacks (α = 0.05). Average total cumulative attacks were used for the GLIM analysis (Spring 2018: χ ² = 12.3, df = 4, P = 0.0153; Fall 2018: χ ² = 114.39, df = 4, P < 0.0001).