Leaf Blister Research Articles

Eriophyes pyri . [Distribution map

Abstract A new distribution map is provided for Eriophyes pyri (Pgst.) (Acarina, Eriophyidae) (Pear Leaf Blister Mite). Host Plants: Pear, apple, plum. Information is given on the geographical distribution in EUROPE (excl. USSR), Austria, Belgium, Britain, Bulgaria, Czechoslovakia, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Malta, Norway, Netherlands, Poland, Portugal, Rumania, Spain, Sweden, Switzerland, Yugoslavia, ASIA (excl. USSR), Cyprus, Iran, Israel, Lebanon, Saudi Arabia, Syria, Turkey, USSR, AFRICA, Egypt, Kenya, Libya, Rhodesia, South Africa, AUSTRALASIA AND PACIFIC ISLANDS, Australia, New Zealand, NORTH AMERICA, Canada, U.S.A., SOUTH AMERICA, Argentina, Bolivia, Brazil, Chile, Uruguay.

The Control of the Pear Leaf Blister Mite with Endosulfan

Single applications of endosulfan at dosages of 0.25 and 0.5 lb. of active ingredient per 100 gal. of spray were evaluated for the control of the pear leaf blister mite, Eriophyes pyri (Pagenstecher), on young pear trees. Phostex® (a mixture of his (dialkyloxyphosphinothioyl) disulfides (alkyl ratio 75% ethyl, 25% isopropyl)) lime sulfur with oil, and binapacryl were also included in the trials. The treatments were applied at various times after harvest until the delayed dormant period. Based on blistered fruit and leaf cluster counts, endosulfan as well as lime sulfur with oil provided extremely effective control, irrespective of the time of application. The effectiveness of Phostex and hinapacryl was limited to that period in which the fall migration of the mites from the leaf blisters has been completed. Applications of lime sulfur and oil made in September and October caused severe leaf burn and subsequent defoliation. None of the other materials included in the trials and any apparent form of phytotoxicity.

ANew Material for the Control of the Pear Leaf Blister Mite1

Phostex, bis(dialkyloxyphosphinothioyl) disulfides, where the Alkyl groups are ethyl and 2-propyl in a ratio of three to one, is n phosphate insecticide-acaricide of low mammalian toxicity (acute oral LD50, 2500mg./kg. to white rats). Phostex has given excellent control of the pear leaf blister mite, Eriophyes pyri (Pgst.), on pears during 2 years of development and 1 year of commercial use. No injury was detected on pears when Phostex emulsifiable concentrate was used alone in the fall (postharvest) or delayed dormant or when Phostex was used in combination with oil during the dormant period. Phytotoxicity has been observed where Phostex was applied to the foliage of most stone fruits; however, no injury to these trees has been observed with dormant sprays of Phostex-oil combinations.

An Emergency Summer Treatment of Pear Leaf Blister Mite1

An Emergency Summer Treatment of Pear Leaf Blister Mite1

Pear Bud Injury and the Pear Leaf Blister Mite

The destruction of pear buds during the winter months, the abundance of weakened buds at blossom time and russetted, imperfect fruit at harvest time have been observed for many years on trees which did not show blistering of the new foliage.

Notes on the Biology of the Pear Leaf Blister Mite in the West

The older ideas of the behavior of the blister mite (Eriophyes pyri) in the spring are not in accordance with their actual habits in the West. Several writers have suggested this; and the present writers have found that wintering mites deposit eggs in the buds, that blisters are made by the feeding of the generation coming from these eggs, that the mites do not enter the blisters until they are adult, and that this does not occur until the foliage is well out. Sprays applied after the buds have begun to open are apparently effective.

The Bud Mite (Blister mite) of the Pear

Observations on the life history of Blister Mites on pear trees, which differ in habits from those of the Pear Leaf Blister Mite are given in this paper. One reason trees that are fall sprayed with Lime and Sulphur may have many buds killed by mites and yet develop no infestation of the leaves the following spring is given. Control is suggested.