De Meijer, A.H., Wysoki, M., Swirski, E., Blumberg, D., & Izhar, Y. 1989 Susceptibility of avocado cultivars to the pyriform scale, Protopulvinaria pyriformis (Cockerell) (Homoptera: Coccidae).. Agriculture, Ecosystems & Environment 25: 75-82.
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Notes: The susceptibility of avocado cultivars to Protopulvinaria pyriformis was studied in the laboratory at 25 deg C and 70% RH and in the field in Israel during 1985-86. In the laboratory, crawlers were shown to be positively phototrophic but had no clear geotaxis. Eleven days after infestation of seedlings, mortality varied from 62% on Reed to 96% on Horshim. Insects on cultivars Nabal and Ein Vered had significantly higher survival rates than on other cultivars, except for Reed. The development of P. pyriformis was relatively fast on Nabal, Ein Vered, Hass and Pinkerton (pre-ovipositing females after 75 days), but slower on Reed and Ettinger (pre-ovipositing females after 100 days). In the field, Nabal was the most infested cultivar, followed by Hass and Fuerte, while Ettinger was sometimes attacked when close to infested Nabal or Hass trees.
