Timing of insecticide application is important. Never spray a crop in bloom unless it's absolutely necessary. If spraying a crop in bloom is necessary, do the spraying when there is minimal bee activity, preferably during the evening hours. During most summer evenings, honeybees leave fields by 8 p.m. and do not return until 8 a.m. or later the following day. Hazards to bees can be reduced by controlling weeds in crop areas.
Bees often forage on wild mustard and other weeds in bloom.
Elimination of weeds will thus reduce bee kills during peak weed bloom. All too frequently fields in North Dakota are sprayed unnecessarily with insecticides when insect population levels are not serious enough to warrant such treatment. Several sites in any given field should be accurately and carefully sampled to be absolutely sure that insect pest population levels are high enough to warrant control measures. Applicator Precautions Use insecticides that have low hazard to bees. If spraying a crop in bloom is necessary, spray when there will be minimal bee activity, preferably during the evening hours.