16 MASS. EXPERIMENT STATION BULLETIN 358 



gravel, or cinders under the bed. Plants set on land recently in sod are very 

 subject to attack. This can be prevented by keeping the land fallow for a year 

 before planting. Mature bushes sometimes become infested. A solution of 

 sodium cyanide, 6 ounces in 100 gallons of water, applied around the crowns 

 at the rate of 2 gallons per square foot, kills most of the grubs. The cyanide is 

 a deadly poison, and must be used with care. 



Caterpillars of the gypsy moth, Porthetria dispar (L.), sometimes do con- 

 siderable damage but are easily checked b}- spraying with 6 pounds of dry lead 

 arsenate in 100 gallons of water, about May 20. 



Red-humped caterpillars, Schizura concinna Smith and Abbct, sometimes 

 attack the blueberry. They feed in colonies, in August or September, and can 

 strip a branch of leaves in a short time. If only a few are present, they can be 

 shaken from the bush and crushed. Where they are abundant and the crop is 

 entirely off, spray with lead arsenate, 4-5 pounds to 100 gallons of water. If the 

 crop is not all harvested, use a heavy spray or dust of rotenone made up according 

 to the manufacturer's directions. 



The cranberry spittle insect, Clastoptera saiiit-cyri var. samt-cyri Prov., infests 

 blueberry bushes occasionally. It is a sucking insect about an eighth of an inch 

 long, appears usually in early June, and covers itself conspicuously with froth. 

 It is controlled by spraying with: 



Nicotine Sulfate 1 1/3 quarts 



Fish-oil Soap 4 pounds 



Water 100 gallons 



The blueberry fruit fly or blueberry maggot, Rhd'^oletis pomondla Walsh (re- 

 cently described as R. mendax by Curran), is a ver>' troublesome pest of wild 

 blueberries in some sections. It is present in parts of Massachusetts, but is not 

 yet generally troublesome. The adult is a fly, similar to that of the apple maggot 

 but smaller, appearing in late June and early July. The female lays her eggs 

 under the skin of soft, overripe berries. The eggs hatch into small light colored 

 maggots, 1/4 to 1/3 inch long, which work inside the berries. When infested 

 berries fall to the ground, the larvae enter the soil where they pupate and pass 

 the winter. The following summer the flies emerge to reinfest the fruit. They 

 may be killed before egg laying begins by dusting with a commercial dust con- 

 taining 0.60-0.75 percent rotenone, 70 pounds per acre, 8 to 10 days after the 

 adults emerge, and again 7 to 10 days later. Keeping the berries picked so there 

 will be no soft ones aids control. Removing wild bushes around the field also 

 helps. 



Mummy berry is the most harmful disease of cultivated blueberries. It is 

 caused by a fungus, Sclerotinia sp., which rots and mummifies the green or partly 

 ripe fruit badly in some years. In late summer the gray, dry, shriveled berries 

 (Fig. 10) are found on the ground under infected bushes. Sanitary measures, 

 such as removing wild bushes around the planting and brushing the mummied 

 berries into the spaces between the rows and covering them by cultivation, will 

 reduce this disease. Spraying with Bordeaux mixture 5-3-50 (5 pounds of copper 

 sulfate, 3 pounds of stone lime or 5 pounds of hydrated lime, 50 gallons of water), 

 at the beginning and again toward the end of the blooming period appears to be 

 efi"ective also. 



A twig blight of blueberries is caused by a fungus, Phomopsis vaccinii, which 

 causes a decay of cranberries(lO). The fungus enters tender tips and travels down 

 and kills the shoots. From the shoots it may enter older branches and girdle 

 them so that all parts above the girdle die. Infected parts of plants should be 

 cut out and burned. This disease is of minor importance. 



