May 3, 2011 – Little Green Bees Have Landed
QUESTION:
I have about fifty green bees that are nesting in a sand box of a playground area. I would like to get rid of them but do not want to spray pesticides in an area such as this. Someone had mentioned to me that they thought green bees only stayed for a short while and then would leave on there own. Is this correct? These bees do not even remotely appear to be aggressive. What would you suggest?
ANSWER:
I can understand the mixed emotions on this. If these bees were doing their little thing in some soil in my backyard I would stand aside and enjoy them. But, when they are in a children's sandy play area it does bring children into closer contact with an insect that has the "potential", if not the inclination, to sting. These are probably either Cuckoo Wasps in the family Chrysididae or solitary bees such as Sweat or Alkali bees in the family Halicitidae. Other smallish mettalic green bees include leafcutting bees, but these are unlikely to use the soil for nesting. All of these are solitary wasps and bees. They do not have a colony, do not have a queen, do not have division of labor and larvae to take care of, and do not have any instinct to attack someone who gets too close to their nest. The females of some of these solitary bees do have the ability to sting, but so rarely do that their benefit from pollinating far, FAR outweighs any health concern.
Many wasps and bees, including other little ones called digger bees, mining bees, plasterer bees, etc. create channels in the soil that end in a little chamber. In this chamber the female bee places a ball of pollen and the female wasp places some paralyzed insect and an egg is deposited near this food. The adult wasp then is done and does not return, so the larvae develop on their own from this food cache and emerge later as new adults. Again, no social structure = no aggressive tendencies, and the only time a person would be stung would be if the adult female were directly threatened, such as being captured in a hand or trapped in clothing.
The soil has to be of a consistency that the bees or wasps can create tunnels that do not collapse. Drying out the sand would keep them from doing this successfully, and raking the soil daily or more frequently might discourage the wasps. Covering it with plastic to keep the bees off the soil will also cause them to go somewhere else. I agree with you that spraying the sand that children play on with ANY pesticides could raise the concerns of some parents, even if the pesticide were a "natural" material from plant oils. Some people simply are that concerned over anything we could call a pesticide, although they routinely expose themselves to far more toxic substances in their own home or garage than we could use to kill insects.
However, insecticides are not that useful anyhow for burrowing bees and wasps, and making physical changes to cause these insects to look elsewhere for their larval chambers is a better long term solution. You would have to treat each individual hole in the sand if you could find them, and this is time consuming and make not work anyhow. Better to try to make it impossible for the bees to either access the sand or to dig tunnels in it. Dry sand is their enemy.
I have about fifty green bees that are nesting in a sand box of a playground area. I would like to get rid of them but do not want to spray pesticides in an area such as this. Someone had mentioned to me that they thought green bees only stayed for a short while and then would leave on there own. Is this correct? These bees do not even remotely appear to be aggressive. What would you suggest?
ANSWER:
I can understand the mixed emotions on this. If these bees were doing their little thing in some soil in my backyard I would stand aside and enjoy them. But, when they are in a children's sandy play area it does bring children into closer contact with an insect that has the "potential", if not the inclination, to sting. These are probably either Cuckoo Wasps in the family Chrysididae or solitary bees such as Sweat or Alkali bees in the family Halicitidae. Other smallish mettalic green bees include leafcutting bees, but these are unlikely to use the soil for nesting. All of these are solitary wasps and bees. They do not have a colony, do not have a queen, do not have division of labor and larvae to take care of, and do not have any instinct to attack someone who gets too close to their nest. The females of some of these solitary bees do have the ability to sting, but so rarely do that their benefit from pollinating far, FAR outweighs any health concern.
Many wasps and bees, including other little ones called digger bees, mining bees, plasterer bees, etc. create channels in the soil that end in a little chamber. In this chamber the female bee places a ball of pollen and the female wasp places some paralyzed insect and an egg is deposited near this food. The adult wasp then is done and does not return, so the larvae develop on their own from this food cache and emerge later as new adults. Again, no social structure = no aggressive tendencies, and the only time a person would be stung would be if the adult female were directly threatened, such as being captured in a hand or trapped in clothing.
The soil has to be of a consistency that the bees or wasps can create tunnels that do not collapse. Drying out the sand would keep them from doing this successfully, and raking the soil daily or more frequently might discourage the wasps. Covering it with plastic to keep the bees off the soil will also cause them to go somewhere else. I agree with you that spraying the sand that children play on with ANY pesticides could raise the concerns of some parents, even if the pesticide were a "natural" material from plant oils. Some people simply are that concerned over anything we could call a pesticide, although they routinely expose themselves to far more toxic substances in their own home or garage than we could use to kill insects.
However, insecticides are not that useful anyhow for burrowing bees and wasps, and making physical changes to cause these insects to look elsewhere for their larval chambers is a better long term solution. You would have to treat each individual hole in the sand if you could find them, and this is time consuming and make not work anyhow. Better to try to make it impossible for the bees to either access the sand or to dig tunnels in it. Dry sand is their enemy.
