Citrus Flat Mite Injury Patterns on Some Citrus Varieties

Abstract

Brevipalpus lewisi McGregor populations exist on all varieties of citrus grown in California. Their feeding may produce scars which subsequently can downgrade the quality of the fruit, except grapefruit, at the packing house. Population levels necessary at various fruit growth stages to cause injury to navel oranges, tangerines, and lemons were determined, but attempts to produce these injury patterns on grapefruit by manipulating the mite population were unsuccessful. Scarring did not occur after the fruit had reached the mid-growth. stage regardless of the population level. Cold-pressed rind oil extracted from Valencia oranges, lemons, tangerines, and grapefruit caused mitelike scars on each of these varieties, including grapefruit, when small drops of these oils were placed on the fruit surface. The oil glands on grapefruit appear to be less numerous than on other citrus varieties and B. lewisi are able to feed around them so they do not release grapefruit oil onto the fruit surface.