Illinois State Florists' Association
DURING THE past two years new materials supplied by several chemical companies have been evaluated for their effectiveness against the 2-spotted spider mite on roses. Some of these materials were used as sprays and some as fumigants. Because of the labor required and the great difficulty of obtaining complete coverage with sprays, we are always looking for an easier method to control spider mites. Tests With Sprays Better Times roses of uniform growth and vigor were utilized for evaluating the spray materials. Three plants in 8-inch pots, suitably infested with mites, were sprayed with each chemical or each concentration of the chemical used. The plants were sprayed by hand with a rod and nozzle attached by hose to a small power sprayer operating at about 150 lb. per sq. in. In order to avoid errors due to uneven deposits of miticides, great care was exercised to obtain complete spray coverage. A count of live and dead mites was made before each test. The results of these counts appear in the "O" column (Days After Treatment) in the tables. Then, at intervals after treatment, samples of leaves were taken for counts of live and dead mites to obtain the results of the action of the chemical. A high kill within 3 or 4 days after treatment indicates effectiveness of the chemical against all stages of the mite, including the eggs. A high percentage kill that gradually declines within 2 or 3 weeks indicates a poor kill of eggs or the presence of surviving mites that continue to lay eggs.
Source: • Illinois State Florists' Association Bulletin # 241
Keywords: Lay eggs Effectiveness roses glue, American Cyanamid 43073, NIA 9044