Pear, Insect and Mite Control, Hudson Valley Lab, Highland, N.Y., 1987

Abstract

Abstract Treatments were applied to 8 tree plots replicated 3 times in a randomized complete block design. Each plot contained 4 'Bartlett' and 4 'Bosc', spaced 12 × 18 ft., 12 ft. high, and 13 yr old. Treatments were applied dilute to runoff using a high-pressure handgun sprayer at 350 psi delivering from 1.9 to 2.9 gal/tree (380 to 583 gal/acre), depending on time of season and leaf canopy present. Danitol was applied at white bud, 20 Apr; petal fall, 8 May, and in cover sprays on 23 May, 7 and 24 Jun, and 13 Jul for the first treatment. The same rate was applied in a reduced schedule (20 Apr, 8 May, 7 Jun, and 13 Jul) as a comparison for the second treatment. Danitol was also applied along with Superior oil on 8 May. This application was followed by Guthion applications on 23 May, 7 and 24 Jun, and 7 Aug. There was a Mitac application on 13 Jul. Abamectin was applied at 3 different rates without oil on 8 May and with oil on 7 and 24 Jun, 13 Jul, and 7 Aug. Asana was applied 20 Apr, followed by Zolone + Sevin on 8 May, and Zolone + Mitac on 7 and 24 Jun, 13 Jul, and 7 Aug. An additional appliction over the entire block for fire blight control consisted of Agri-Strep, 8 oz/100 gal on 13 May. Applications were made for Fabraea leafspot control on 11 Jun and 1 Jul. Each replicate was treated with a separate fungicide at these applications. One replicate received Manzate 200 80W 1.5 lb/100 gal, another received Captan 50W 2 lb/100 gal, and the third received Benlate 50W 2.0 oz/100 gal + Manzate 200 80W 1.5 lb/100 gal. Pear psylla were evaluated by collecting 5 'Bartlett' spurs (25 leaves) from each plot on 7 and 18 May and 4 Jun and thereafter 5 'Bartlett' shoots (25 leaves) from each plot on 15 Jun, 3 and 20 Jul, and 4 and 13 Aug. All live nymphs and eggs on each leaf were counted in the laboratory using a binocular microscope. Mite populations were assessed by examining 5 'Bartlett' leaves per plot from the 20 Jul pear psylla sample. These leaves were viewed with the aid of a binocular microscope, and all live mites were counted. Insect injury was evaluated by examining 50 'Bartlett' fruit per plot harvested on 4 Sep. Rainfall during May and June was less than normal; during April and July rainfall was above normal. April and July temperatures were above normal and temperatures in May and June were below normal. Pest pressure, especially pear psylla and pear rust mite, was greater than usual due to the early onset of warm weather in the spring.