What to do about the spots on your apple leaves

PRESTON — Blister mites are a communal show successful backyard orchards. In nan summertime and fall, their harm tin beryllium seen arsenic brownish raised “blisters” connected nan leafage surface. In our area, nan astir communal blister mite successful nan orchard is pear and apple-leaf blister mites. Blister mites are excessively mini to beryllium seen without magnification.

These mites beryllium to a group called eriophyid (er-ee-oh-fy-id) mites. Eriophyid mites are translucent, cigar-shaped microscopic mites that origin deformities connected galore works species.

These mites are noticed erstwhile their feeding causes abnormalities of works tissues specified arsenic galls, brooms, leafage curling, blisters, rusts, silvering, consequence russeting and deformed buds, etc. Fortunately, these mites seldom origin superior harm to plants, and power is seldom needed.

Some mites are big specific, while others onslaught galore works species. The mites mostly overwinter arsenic fertilized big females nether bud scales aliases protected sites connected aliases adjacent nan big plant, emerging astatine bud break successful spring. Both males and females are coming passim nan increasing season. Reproduction is continuous, pinch generations completed each 2 to 3 weeks.

If populations are high, blister mites connected pome and pear leaves tin trim photosynthesis and character vigor. Treat dense infestations successful early autumn (October) earlier leafage drop, erstwhile mites are migrating from leaves to buds. Options see carbaryl, horticultural lipid aliases lime-sulfur. Horticultural lipid applications successful outpouring astatine bud break are besides effective. Blister mites cannot beryllium treated successful summer.

Because eriophyid mites are mostly a cosmetic issue, you should favour reduced-risk curen options (oil aliases sulfur). Beneficial predatory mites provender connected eriophyid mites and different pests. Reduced-risk curen options minimize impacts to nan predator mites arsenic good arsenic beneficial insects. As you sphere beneficial type you support section ecological integrity and will acquisition less (seed) disease outbreaks successful nan future.

Beneficial predatory mites feast connected nan harmful eriophyid mites. | Courtesy Bracken Henderson