Seasonal Activity and Control of the Monterey Pine Tip Moth

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Abstract
The Monterey pine tip moth, Rhyacionia pasadenana (Kearfott), occasionally causes severe damage to pines in coastal California. The insect has a single generation each year. Injury results from the tunneling of larvae first within the needles and later within shoots. In studies conducted in Richmond, Calif., the pupa was the most important overwintering stage both in 1962 and 1963. Moth emergence occurs during 10 months of the year, with the peak of flight occurring in the spring. Most of the eggs were found in mid-May. Larvae occur from late April until December, and numbers found ranged from 1 to 27 per infested tip. Heavy larval mortality, owing to unknown causes, was found in the fall. Pupation takes place within the killed shoot tips; pupae are found throughout the year. Effective control of larvae, and good protection of pines from damage, were afforded with a spray of DDT at 2 lb active material, or dimethoate at 0.5 lb active material per 100 gal of water applied May 24, 1963, after egg hatch had begun. Damaging levels of Oligonychus sp. mites developed 2/3 of the trees treated with DDT; treatments made in March resulted in greater mite damage than sprays applied later in the spring.