Environmental Entomology (1995) 24, 1018-1023

Y. Yang, J.C. Allen, J.L. Knapp and P.A. Stansly (1995)
Frequency distribution of citrus rust mite (Acari: Eriophyidae) damage on fruit in 'Hamlin' orange trees
Environmental Entomology 24 (5), 1018-1023
Abstract: Frequency distribution of the citrus rust mite, Phyllocoptruta oleivora (Ashmead), damage on 'Hamlin' orange, Citrus sinensis fruit was studied from 24 August to 13 October 1993, in Lake Alfred, FL. The study plot consisted of 4-yr-old Hamlin orange trees, with a north-south row orientation. Fruit on the north quadrant of the tree were found to have the highest mean surface damage, followed by the east, south, and west quadrants. The frequency distribution of fruit surface damage changed with mean damage levels. When the mean damage was low, most of the fruit had no rust mite damage. With increasing mean fruit damage, the proportion of fruit without damage decreased, and the proportion of fruit with higher damage correspondingly increased. The resulting frequency distribution changed from an exponential decay curve to a more or less symmetrical unimodal curve, with the peak shifting toward higher damage classes as mean fruit surface damage was increased. The frequency distribution was fitted to a 2-variable logistic distribution function of mean fruit surface damage and damage class, using maximum likelihood estimation method. Fruit without rust mite damage was considered a discrete point at zero, and its relative frequency was determined as the height of the cumulative logistic at zero. The model approximated the actual data well at low mean fruit surface damage, but gave a poor fit at high mean values.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Philip A. Stansly

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution
damage/losses/economics

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Phyllocoptruta oleivora	Citrus (genus)	U.S.A. (SE)