DEPARTMENT REPORTS. 131 



ber of sprayed orchards, tlie worms made considerable headway, largely 

 due to the use of too little arseuate of lead in the sprayings before and 

 after the blooming period, thus permitting the larvae to attain consider- 

 able size, and making it difficult to kill them Avhen spraying for their 

 control began in earnest after the fruit had set. 



When allowed to feed unchecked, this insect will not only destroy 

 the fruit crop but will kill the trees if allowed to strip them for three 

 or four years. To control them, the trees should be kept covered with 

 an arsenical from the time the worms hatch in May until they have all 

 been killed. It will not do to begin spraying when the Avork of the in- 

 sects on the trees can be seen. 



Two pounds of powdered arsenate of lead or one and one-half pounds 

 of arsenate of calcium should be used for 50 gallons of water. The 

 latter is the more effectual but as it is likely to injure the foliage, three 

 pounds of lime should be added. 



The first application should be made just before the blossoms open. 

 In case the weather is cold and wet, and the opening of the blossoms 

 is delayed for a week, another application should be made to orchards 

 that are known to be infested. 



As soon as most of the petals have fallen another application should 

 be made, and repeated in ten days or two weeks. In case the insects 

 get much of a headway before the trees are sprayed, the amount of 

 the arsenical may be increased to 2i/2 or even 3 pounds in 50 gallons of 

 water. 



WHITE I'lNE BLISTER RUST INSPECTION. 



Owing to the small apportionment of funds for the work of the de- 

 partment very little white pine blister rust scouting has been done, ex- 

 cent as it could be done in connection with the regular w^ork. 



Fortunately we had arranged to cooperate with the Federal Depart- 

 ment of Agriculture in this branch of the inspection service, and the 

 State was again quite generally covered by scouts furnished and paid 

 by the Federal department. Since July 1, 1919, not a single tree infect- 

 ed with the white pint blister rust has been found in Michigan. In 

 this we are more fortunate than Wisconsin and Minnesota where the 

 disease has become widespread and all hope of wiping it out has been 

 given up. The same it true of large sections of New York, New England 

 and Ontario where it first appeared in this country. 



Arrangements we trust can be made for continuing the scouting, 

 especially along the Wisconsin and Canadian border and in sections 

 where the trees from nurseries in which the disease was found have been 

 jd anted. 



ERADICATION OF THE COMMON BARBERRY. 



Not only has the lack of funds prevented the department from con- 

 tinuing the special inspection work for the locating and bringing about 

 the destruction of the common or tall barberry, which spreads the spores 

 of the wheat rust, but the Federal funds available for the purpose have 

 also been veiy small. 



Very little work has been done except by AValter F. Eeddy who was 

 assigned by the Department of Agriculture to take charge of the work 



