-3- 



(6) For quick knockdown at cookouts , outdoor parties, or picnics, use either 0.1- 

 percent pyre thrum or 0.5 -percent dichlorvos (DDVP) solution as an oil- or water-base, 

 space spray. Spray the mist lightly beneath tables and chairs and into the air for 

 a few feet around the area. Repeat the treatment as needed. 



Oystershell scale. The second- generation crawlers have hatched in the southern part 

 of the state. The hatch is just starting in the central section. The first genera- 

 tion began earlier than normal this year. Many shrubs were infested with new scale 

 in late May and June. Treatment for these crawlers was often too late. If oyster- 

 shell scale is a problem on lilac, birch, willow, or other tree and shrub species, 

 spray the infested areas with malathion. Apply treatments now in the southern sec- 

 tion and during the week of August 6 in the central section. Repeat in ten to four- 

 teen days . 



Squash vine borer . These moths can be observed flying about vine crops, such as squash, 

 melons, and pumpkin. These red-bodied, clear-winged moths lay dark-red eggs on the 

 stems of the vine crops. The eggs hatch into tiny worms that bore into the stems and 

 feed on the inside of them. This feeding causes one or more runners on the plant to 

 wilt and die, sometimes killing the whole plant. Squash vine borers can be controlled 

 by either dusting or spraying with carbaryl (Sevin) at seven- to ten-day intervals, 

 beginning when the plants start to produce runners. 



Mimosa webworms . They continue to spin webs on the branches of honey locust trees and 

 to feed on the enclosed leaves. The infested trees are easily recognized by the masses 

 of brown, dead foliage on the tips of the branches. All stages of this insect are pres- 

 ent at this time. Apply a spray of carbaryl, malathion, or Bacillus thuvingiensis (Bi- 

 otrol, Dipel, or Thuricide) . A second treatment in about two weeks may be needed. 



PLANT DISEASES 



BROWN SPOT DISEASE OF SOYBEANS 



This disease is caused by the fungus Septovia glycines Hemmi , has been on the increase 

 in the Midwest during recent years. The disease appears as reddish-brown lesions that 

 vary from the size of pinpoints to a fifth of an inch wide. Heavily infected leaves 

 gradually turn yellow and may fall prematurely. In severe cases, the lower half of the 

 stem may be bare of leaves before maturity. 



The fungus overwinters in seed and in diseased stems and leaves that are left in the 

 field. The greatest damage may occur in fields where soybeans are planted every year. 



NOTE: Seed treatment does not satisfactorily control brown spot. None of the commer- 

 cially grown soybean varieties are resistant. 



For more information about brown spot of soybeans, write to the Department of Plant 

 Pathology, 218 Mumford Hall, Urbana, Illinois 61801. Ask for Report on Plant Dis- 

 ease No. 503, "Fungus Foliage Diseases of Soybeans." 



THE CURRENT PICTURE 



To provide insight about the plant diseases currently appearing in Illinois fields and 

 gardens, here is a list of diseases that were diagnosed in our plant disease clinic 

 this week: 



