Monitoring for ForagingMonitor Hives as an Aid to Compliance
Monitoring for Foraging
A simple way to determine if bees are visiting cotton flowers is to check returning bees at the hive entrances for their pollen "packets." Here you can see returning foragers with cotton pollen. Cotton pollen is very pale yellow, nearly white. It is often the only pollen available in quantity, at the time of year that cotton blooms (in coastal SC anyway). Bees comb the pollen from their fuzz, and pack it into pellets in the pollen baskets on their rear legs.
One or two hives can be placed near cotton fields, where an applicator can drive up to them in a closed vehicle, and observe for the cotton pollen pellets. When bees are no longer bringing in cotton pellets, they are done working in the cotton, and it is safe and in-compliance to spray insecticides.
When bees switch to water carrying (very common in hot weather), the returning bees will have no pollen pellets, and they will enter very quickly. The bees will do a lot of fanning at the entrance -- a sign of heat stress.
Monitor hives can be arranged with a beekeeper who does pollination service. He is already set up to move hives from crop to crop, and this is likely a lull time in his season. In addition, he is vitally interested in making sure applicators comply with label directions, so as to NOT kill bees. He may even "cut a deal" or provide the monitors for free. On the other hand he is engaging in a calculated risk, that you will keep your promises, obey the law, and apply according to the monitor indications, so he could charge more than normal pollination rates.
Monitoring for Bee Damage
A few bees die of old age every day, and there is
always some damage, when bees are close to sprayed cotton. Even if there is full
compliance with the label, a few guard bees at the entrance may catch a droplet, or bees
may be overflying the field to get water, and catch a droplet. This may result in a few
dead bees at the entrance. Twenty to fifty bees are not of much concern at this point, as
long as the hive stays in good shape and continues to gain weight.
But indications of failure/likely misuse include:
Sudden reduction in flight after application/loss of field bees in the field/dead bees in cotton rows. This indicates application of a quick acting, but non-residual material while bees are visiting cotton blossoms.
Piles of dead or crawling bees near the entrance - indicates application of a highly residual material so as to contaminate nectar/pollen
Loss of weight of the hive during cotton bloom.