Leaf cutter bees are a solitary insect. This means each nest is independent of others. However, it is most common to find several nests in close proximity of one another without conflict. Their territories can be quite extensive – over several acres – depending on local food and shelter. And since there are hundreds of species found throughout the lower 48 states of America, they can vary in color and size. Many look like common honey, bumble and carpenter bees but the one sure clue they’re leaf cutters is when you’re finding solitary nests with plant parts inside.
Leaf cutter bees will overwinter in prepupal and pupal stages. They are among the earliest if not the very first bee to begin pollinating. They are not too sensitive to bad weather and will readily work when most other bees will remain home in the comfort of their colonies. For this reason Leaf cutter bees are highly desirable – except when they’re damaging your plants!!
LEAFCUTTER BEES ARE GENERALLY BENEFICIAL
In fact, leaf cutter bees are so desirable many gardeners and farmers actively install LEAF CUTTER BEE HOUSES around their property. Hang them on fence posts or trees and you too can attract them to your land.
Nesting bees will work the landscape in and around your property insuring healthy pollination. With Honey Bee populations declining, the installation of these homes can have a big impact on local plants.
Furthermore, making leafcutter houses readily available around the yard, they will help reduce nesting activity on your house!
LEAF CUTTER BEE BIOLOGY
As the weather warms, Leaf cutter bees will begin to emerge and immediately start looking for plants to fix old nests or build new ones.
Nest sights will be cavities which range from 1 inch to several feet deep. Such cavities can be found anywhere and are generally preferred to be around 9/32 to 5/16 of an inch wide in diameter. Such cavities can be found in old tree stumps, rocks, the ground or even live trees. In fact, they will readily take advantage of old mud dauber and paper wasp nests! Once a suitable nest is located, queens will actively search for food – pollen – along with nest sealing material. During this time she will mate so fertile eggs will be produced as the nest is constructed.
LEAF CUTTER BEE NESTS
Nests are constructed by first placing food in the chamber, next laying an egg on the food and lastly by sealing the egg and food with a type of plaster. This plaster is usually made from mud or some cellulose product like paper or old wasp nests. It can also be made from plant parts like leaves (their favorite material to use).
Once sealed, the eggs will have all they need to develop and grow and one day they will emerge ready to continue the process. Since nests are dependent on a healthy supply of pollen, expect to have activity during any one growing season. For this reason northern territories may only have one generation active per year but southern regions could have several develop.
Leaf cutter bees are generally passive and not very aggressive. However, they can sting and will do so if handled or aggravated. For this reason they are best left alone. However, the opportunity for nest sights on homes is great. This is why this bee can become a major nuisance if nesting is ignored. Furthermore, they can cause damage to both homes and plants which is unsightly and unacceptable.
WHERE DO LEAF CUTTER BEE NEST?
Leaf cutter bees will readily nest on any structure which presents a prime location. One of the more common locations they like are the weep holes found around windows and doors. Such weep holes are common on brick homes but are used more today then ever as a way to help keep moisture from rotting the structure. Furthermore, builders will commonly use tubing in these weep holes which leaf cutter bees love! They will readily find such tubing and quickly nest in it. When sealed, the tubing will cease to function causing moisture and water problems for the building
NESTS CAN DAMAGE HOMES
Leaf cutter bees can also create their own nests when none are easily found. They will chew through wood, mortar and stucco and though such chewing is usually not going to hurt the structural integrity of the building, it will certainly be unsightly.
Cedar and masonite sided homes are not immune to this behavior and virtually any overhangs will attract them to soffits and fascia boards. Holes in such areas are usually shallow and small but will certainly be both annoying and aggravating. Leaf cutter bees have learned that most any home has an abundant supply of nest locations and taking advantage of them seems to be at an all time high. It appears that once a house has activity it will get more and more every year. This probably happens because if a structure has something unique about it which leaf cutter bees like, female queens will leave special pheromones used to “mark” structures as a good place to live. This means once your home gets “marked”, bees will be coming around looking to nest.
LEAF CUTTER BEES WILL DESTROY FLOWERS AND SHRUBS
Leaf cutter Bee nests on the home can become a problem but the damage they do to the structure is generally superficial. However, in the yard, their damage can be quite real and have major impact on targeted plants.
Leaf cutter bee damage is done when they remove leaves from plants by cutting away small circles around the size of a dime. In fact, it is very common for them to find a shrub or plant they find attractive and within a week or two, the plant has no leaves. When such damage happens rapidly, the plant may never recover from it’s loss. Remember, leaves play an important role for any plant. Without them they are not able to create food and eat. And if there are a lot of bees active, certain leaves will begin to suffer huge tissue loss and die; some will fall victim to plant disease or other insects.
HOW TO STOP LEAF CUTTER BEES
Plants which are targeted by leaf cutter bees usually have some characteristic or feature they want. For this reason a few sections of leaves removed turns into a few more and soon a lot more. Damage will happen quickly since these bees work around the clock.
If you find activity that is damaging a prized plant or some fruit or vegetable, we have several concentrates you can apply to either chase them away or kill them.
BEST LEAF CUTTER REPELLENT SPRAY
The first way to keep leaf cutter bees off your plants is to spray them all with MAXXTHOR EC. This concentrate mixes with water and is highly repellent to all insects. Bees will readily detect its presence and stay off any plant you spray.
Mix 1 oz per gallon of water and treat plants you want to protect in the evening, just before dark. Leaf cutter bees are most active at night so treating right before dark is a good time to get a fresh barrier in place. Within a few days of being treated, local bees will change their foraging habits and begin looking for plants elsewhere.
Maxxthor will last 2-4 weeks so plan on treating ever 2 weeks if they come back. But once gone, once a month should keep them away.
And since the bees will detect the Maxxthor, they won’t affected, they’ll simply stay away, so you don’t want to kill them this is a great option.
BEST LEAF CUTTER BEE KILLER
If you’re not content just repelling the bees using the Maxxthor above or the Multi Purpose Insect Repellent below, spray the plants they’re targeting with PROTHOR. This non-repellent concentrate is commonly used on plants for both foliage and systemic spray to stop whiteflies and aphids. As a non-repellent, insects won’t notice its present and continue to forage where its been applied. This will cause them to pick up small doses and after 2-3 days, they’ll die.
Prothor should be mixed at a rate of 1 oz per gallon of water and should be applied to the leaves they’re targeting. In most cases there is no need to spray the flower of the plant being attacked but if you have budworms or something else eating the new growth, spray it all. But if its just the leaves, a low pressure spray on the leaves will do the job fine.
For season long systemic control, soil drench around plants using 1-2 gallon of mixed solution per 25 sq/ft of turn where plants are bedded.
When foliage spraying, plan on treating every two months. When systemic spraying, one treatment per season will do the job for the whole year.
BEST SPRAY FOR THE VEGETABLE GARDEN
If you have bees targeting a vegetable bearing plant or fruit producing tree, use MULTIPURPOSE INSECT REPELENT. This concentrate is similar to Maxxthor in that it will repel bees from the treated surfaces. Mix 2 oz per gallon of water and plan on treating once a week when bees are active.
Multipurpose is safe enough to use on any vegetable or fruit bearing plant so you can still eat the crop (assuming they can still produce a harvest) even spraying right up to just one day to harvest. But it has no true residual so we have found it wears away quickly and at best you’ll get 7 days of protection.
When deciding how many plants you should treat, the rule to follow is simple. When a plant starts to experience leave damage due to leaf cutter bees, you need to treat. If you have several plants of the same species, treat all of them. This will be needed because if you treat only one the bees will simply move to the untreated plant since it is the same species. If you only have one plant, you only need to start by treating that plant. Next, watch to see where they move. It is possible they will move to some adjacent plant which is a completely different species altogether or they could move to vegetation which is not even located on your property. Since you cannot be sure there is no need to broadcast your applications. Instead, play a wait and see game to learn just where they appear next and then treat that plant accordingly. Once applications begun, expect to perform followup applications every 2-4 weeks depending on local activity and populations.
To apply any of the products above, you’ll need a good PUMP SPRAYER. In most cases, there will be no need to pump it up much as low pressure will prevent wasteful run off unless you need to reach a height of 10 feet or more. Our sprayer can reach over 15 feet for tall shrubs.
BEST LEAF CUTTER BEE DETERRENT THAT WON’T KILL THEM
If you only want to repel the bees and not kill them, get our PEST AWAY. Derived from plant essential oils, this concentrate works by scaring the bees into thinking something is not right with the treated plant. Essential oils are natural but when they appear at “unnatural” levels, it confuses insects and animals.
In this case, mixing 2 oz of Pest Away to a gallon of water and spraying the flowers, shrubs or any other plant they’re targeting. Once in place, the Pest Away will naturally “guard” the plant by keeping damaging cutter bees away.
Treatments can last 2-4 weeks but for the initial 1-2 months, plan on treating once every 10-14 days until the bees learn to go elsewhere.
HOW TO TREAT NESTS ON THE HOME
Leaf cutter nests on the home may not sound like a big deal but they can become a major problem. Such activity usually starts out innocently and then blossoms into a major concern a season or two later.
The areas where they nest dictates just what products you should use and how they should be applied.
If you have bee nests forming in weep holes or the tubing used for weep holes, it is important to keep these open and clean. Bee nests will quickly clog them and prevent proper water drainage. This blockage could lead to several other problems including water damage, termites and carpenter ants.
To stop this from happening, there are two things you need to do. First, try to identify all weep holes around the structure. Next, clean them out making sure to remove all nests and nest components. The best way to do this is with a small drill bit or tiny screw driver. You can use a thin rod like a coat hanger too but many times all this does is push the nest further up the tube.
Once you’re sure the holes open, inject FS MP AEROSOL using the included application straw. FS MP is fast acting and like the Maxxthor, highly repelling to all insects. It will kill any in the next when applied but any away will not use the treated next and in turn, move elsewhere. Spray into any hole hole or next you find for 3-5 seconds in early evening and do this for 3 evenings in a row.
FS MP will work immediately. As the bees sense the treatment, they’ll move away and start nesting elsewhere.
Give us a call if you need further help. Our toll free is 1-800-877-7290 and we’re open Monday through Friday, 9:00 AM to 4:00 PM. On Saturday, 9:00 AM to 2:00 PM (Eastern Standard Time).
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Barbara Toothman says
How can u say Leaf Cutter Bees are beneficial when they have destroyed several of my plants. I am chasing one now, very clever n fast. He’s destroying my naval orange blossoms. I’ve been using “wasp stray” because of its trajectory. Seventeen foot tall tree and I work so hard to get it to fruit. My neighbor is yielding fruit, black bee will not leave my plants alone. I don’t understand beneficial pollinator if he eats the entire rose plant???
Tech Support says
Barbara,
We have not determined that any insect is “beneficial” or “destructive” by nature; we merely report what the scientist have categorized them to be. In general, any bee or wasp that “pollinates” is considered to be beneficial and as such, leaf cutters fall into this category. This does not mean they can not be destructive as well.
In this case, its clear you have a beneficial bee that is also destructive. Carpenter bees are the same; they too pollinate flowers but they also drill holes in homes and if left untreated, can cause massive damage to structures. Same with Mason bees. In all three cases, these bees are both beneficial and destructive.
Long story short, if you read our article above you will see we make no mention of any “wasp freeze” to control leaf cutters. Why? Simple, bee freeze products won’t work. They are both wasteful and they will damage the very plant you’re trying to protect. Instead we suggest you get one of the listed concentrates we have and solve the problem.
The Maxxthor is the strongest and once applied, will keep all bees and wasps off treated plants. It won’t kill them but it will repel them from the area. So too with the Multi Purpose Insect Killer which is safe enough to use on plants yielding edible harvests like applies/oranges, etc.
And if you intend on killing the culprit, go with the stealthy Prothor. It won’t work fast but within 2-3 days, any bee or wasp targeting a treated plant will be dead.
Technical Support
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