Determining an economic injury level for the persea mite, Oligonychus perseae, a new pest of avocado in Israel

Yonatan Maoz, Shira Gal, Miriam Zilberstein, Yoanatan Izhar, Victor Alchanatis, Moshe Coll, Eric Palevsky*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


The persea mite, Oligonychus perseae Tuttle, Baker & Abbatiello (Acari: Tetranychidae), a pest of avocado, was first discovered in Israel in the autumn of 2001. It has since spread to most avocado growing areas in Israel. To establish an economic injury level (EIL), based on the percentage of leaf area damaged (PLAD), we conducted an extensive field study. For three consecutive seasons we created distinct pest infestation levels on the Hass avocado cv., by applying acaricides (spirodiclofen and abamectin) at 50, 100, and 250 mites per leaf levels, along with non-sprayed controls in a replicated block design. At harvest time we evaluated the level of leaf damage and fruit yields across treatments. In two out of the 3 years, trees sprayed at 50 and 100 mites per leaf levels had similar PLAD values, differing from trees treated at the 250 mites per leaf level and the non-treated control, the latter pair also being similar. Over the 3 years, mean yield attained at the two higher infestation levels was reduced by 20% in comparison to the mean yields recorded for plots sprayed at the lower thresholds. Accordingly, we suggest that scouts adopt an action threshold (AT) of 50-100 mites per leaf. Future research is needed to refine this AT. Mean annual cumulative mite days (CMDs) of the two higher levels was ca. 13500 ± 700 per leaf. Using the linear regression equation PLAD = 0.0009CMDs + 2.42, describing leaf damage as a function of CMDs, we estimated an EIL of ca. 15 PLAD.

Original languageAmerican English
Pages (from-to)110-116
Number of pages7
JournalEntomologia Experimentalis et Applicata
Issue number2
StatePublished - Feb 2011


  • Acari
  • Action threshold
  • Cumulative mite days
  • Damage threshold
  • Percent leaf area damage
  • Tetranychidae
  • Yield


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