By: Phil Craft
A beekeeper in Kentucky writes –
I always enjoyed your tips when you were our state apiarist, and your “Ask Phil” column in Bee Culture is the first thing I turned to each month. My question concerns small hive beetles, which apparently was a major issue in Kentucky this year. I had one beeyard with just two hives, and when I concluded they had a mite issue early in the Fall, I put in Miteaway Quick Strips( MAQS), which I’d never used before (hadn’t treated with anything for several years). The day after I put in the strips, a robbing frenzy began that I was unable to stop. I’d hoped at least it was one colony robbing the other so that I might lose only one hive and retain the stored honey, but alas, the thieves came from elsewhere and wiped out both of them.
When I opened the dead-out hives a couple days later, I found them absolutely crawling with hive beetle larvae, which took hours to clean out so I could freeze the frames. On the advice of another beekeeper, I mixed up a slurry of mineral salt and dumped it where the hives had been in an attempt to kill the pupating beetles in the ground.
My question is how to proceed in the future. Is mineral salt effective, and how large a radius around the hives must be treated? Should I leave that yard hiveless for a year to interrupt the beetles’ life cycle, or do they not winter over in the ground anyway? Would putting the hives a couple hundred yards away make any difference at all?
I’ve also put vegetable oil traps in some other hives in which I’ve seen beetles, but they’ve caught only a couple of them. Those colonies look strong otherwise, but I didn’t get down into the bottom box for fear of setting off another robbing frenzy.
Any advice you can offer would be most appreciated – by a lot of Kentucky beekeepers, I’m afraid.
In most of the U.S., adult small hive beetles (SHB) are common squatters and pests, and last Summer’s rain and humid weather in Kentucky created more favorable conditions than usual for their proliferation. I’m sure that, as beekeepers, we would all like to completely eliminate them from our hives. Hence the numerous commercial beetle traps, designs for homemade traps, and suggestions for soil treatments to kill the beetles in the pupa stage. However, SHB are very difficult to eradicate. You can never kill them all, and if you could, they would quickly repopulate. Adult beetles can fly several miles, are attracted to odors from hives, and are capable, as you observed, of producing thousands of larvae in weak or dying hives, as well as in unmanaged, feral colonies. As the colonies collapse, the remaining bees abscond – fly away to seek out a new home. The adult beetles also fly away to find new honey bee colonies to establish themselves in. Therefore, even if we dramatically reduce the number of adults beetles in a hive, it’s likely to be only be a temporary victory. Because of this, the most practical method of managing SHB is to maintain strong colonies.
A colony with a strong, healthy population of bees can control a large number of adult beetles and prevent damage to the hive. (I’ve touched on this topic in a previous column; see the June 2013 issue of Bee Culture.) Honey bees will literally herd adult beetles into the inner corners of the hive or of the inner cover, and inhibit their reproduction by separating them from their favorite egg laying location – in or on the edge of brood comb. They prefer the periphery of the brood because, like honey bees, small hive beetles require pollen to reproduce. We often refer to the corralled adult beetles as being held in bee jails. Understandably, controlling them in this way becomes more difficult as a colony’s population drops because of Varroa, disease, or queen problems.
In this case, what caused the sudden explosion of SHB larvae in your hive and what set off the robbing? I suspect that all three events; the Varroa problem (possibly including your treatment of it), the sudden appearance of the beetle larvae, and the robbing, were interrelated and that they all began with mites – especially since you say you haven’t treated with anything in several years. Varroa mites weaken hives, and both robbing and the production of large numbers of SHB larvae are common problems in weakened hives. In addition, opening the hive as you did to insert the MAQS, may have disrupted the bees’ efforts to control the beetles. You may have unwittingly aided a jail break, but I suspect that it was a jail break waiting to happen. The robbing most likely occurred after the larvae explosion, but it’s possible that it happened first and provided an opportunity for the SHB. The bottom line is, weakening of the hives by a Varroa infestation is probably what started this sequence of events. I suspect that you waited too long before attempting to control the mites.
Let’s talk about the strategies you mentioned for controlling SHB in the future. Applying salt to the ground around a hive is an attempt to interrupt the beetles’ reproductive cycle by drying out the soil. As you indicated, SHB larvae must leave the hive and make holes in order to pupate underground. To do that, they need moist earth. Treating the ground around a hive with salt may make it less hospitable to the larvae and perhaps somewhat reduce their ability to achieve the next stage in their life cycle, however, SHB larvae are capable of crawling long distances. Most of them will probably just crawl to untreated soil. This may be true for any method of ground treatment. Leaving the bee yard hiveless for a year would more effectively interrupt the cycle because, as you suspected, small hive beetles do not Winter in the ground. Only the adults live through the Winter, and they survive by moving into the colonies’ wintering cluster during cold weather. Unfortunately, moving hives – either a few hundred yards or to a different beeyard – does not eliminate beetle problems since the beetles move with hives. One thing which will help is destroying the SHB larvae from your dead outs. Don’t let them get into the ground. Dumping the larvae and larvae containing frames into a bucket of soapy water will kill them quickly. If the frames are not heavily damaged they can be rinsed off with a hose, dried, and re-used.
I typically have large numbers of adult beetles in my hives and while I occasionally do some trapping, using the small traps that fit between the frames, I have never used ground treatments and rarely suffer larvae damage in my hives. The times when I have had a problem have involved hives that have become very weak, usually due either to the loss of a queen or because I made a new nuc without enough bees to control the beetles. I have always considered these instances to be as much a management problem on my part as a SHB problem. My response is to quickly combine weakened colonies or to disassemble them and remove them from the apiary, shaking any remaining bees from the frames, before the beetles have a chance to gain control.
Of all the management techniques available to beekeepers to control SHB, maintaining strong, healthy colony populations is by far the most effective. That means monitoring and/or treating for Varroa and maintaining queen right colonies. We need to think of adult beetles as predators waiting for an opportunity. The opportunity comes when the population of a hives declines or is weakened and the bees lose control. Listen to any talk on small hive beetle control or read articles on this topic and you will hear the same refrain: maintain strong colonies.
A new beekeeper asks –
I think my bees have enough honey to get them through the Winter, but I’m not sure after that. Should I start feeding my hives in the Spring?
Hives should be fed, not according to the season (though there are specific times of year when they are most likely to benefit from supplements), but depending on available food stores and nectar sources. I often draw an analogy to farmers feeding hay to their cows. (Many of the beekeepers in my neighborhood also keep cattle.) They feed with hay, not by the calendar, but rather when there isn’t sufficient grass in the fields for cattle to subsist on. We should think about feeding bees in the same way. Hives should be given supplemental feed (typically sugar syrup) when there is insufficient stored honey in the hive, and a lack of nectar for the bees to collect.
How much honey is sufficient? At any time, a healthy hive should contain at least 10 to15 pounds (the equivalent of about four deep frames) of honey to provide for the colony’s immediate needs and to get them through cool or rainy weather when the bees cannot fly to forage. During certain times of year and under certain conditions, such as in winter or during periods of drought, hives require greater quantities of stored food. Without a sufficient amount going into Winter, a colony may exhaust its stores before Spring flowering brings a fresh supply of nectar and pollen, and it will need supplemental feeding to survive. In fact, most Winter starvation occurs in the late Winter or early Spring, so you have reason to be concerned at this time of year.
However, instead of feeding automatically in early Spring, you should first check your hives’ honey stores. It is important to know, in the Fall, what your hives food stores are like and to feed, if necessary, before the onset of cold weather. If you’re unsure about the stores in your hive and if weather permits (see the question and answer in my Bee Culture February 2013 column about Winter feeding and opening hives), open them up and have a look inside. If not, you can get a rough idea by hefting, or lifting up on, the back of each hive. While not as accurate as direct inspection, hefting your hives can help you gauge approximately how much honey is inside by the weight alone. Even with little experience, you can conclude that when a hefted hive feels very light, it is also light on food stores and that emergency feeding is in order. Emergency feeding of hives in danger of starvation should be done using heavy syrup (two parts granulated sugar to one part water) or, as an alternative in the very early Spring, using bee candy. (again, see my February 2013 column for more on emergency Winter feeding).