Travelling recently to Aberdeen, I was struck by the swathes of giant hogweed along the banks of the rivers Spey and Deveron. Just like Himalayan balsam, this plant was introduced by the Victorians as an exotic garden plant and it is now truly established as a harmful non-native species across the length and breadth of Britain. However, like its counterpart, it is a great source of pollen and nectar for a variety of pollinators.
Public Health Risk.
Due to high levels of chemicals called furanocoumarins, touching this plant can cause severe problems. The toxic chemicals react on the skin in sunlight resulting in severe burns requiring hospitalisation in some cases.
These rather imposing and impressive plants are native to the Caucasus Mountains, Southern Russia and Georgia. The earliest recording of their arrival in the UK is 1817 when the Royal Botanical Gardens, Kew received some seeds from Gorenki Botanical gardens in Russia. Gorenki was once a large estate in the city of Balashikha in the Moscow region. They were quickly cultivated and brought to market via the horticultural trade and snapped up by stately homes and estates.
Escape from Cambridge Garden.
Needless to say, giant hogweed escaped and first naturalised around Cambridge from where it broke loose in 1828. Like Himalayan balsam, it spreads quickly via waterways and it took off down the River Cam to colonise further afield.
This plant is prolific and although usually biennial some plants are perennial which means that instead of making leaves only in the first year, followed by flowers and seeds the next, they do all in one year.
It is such a problem that the Scottish Government have guidelines for removing it though there are currently no statutory obligations to remove it from your land.
For further reading check this out:
Beetle Drops By.
Imagine my surprise the other day to hear a loud whirring above my head, as I enjoyed lunch in my favourite garden seat, and have this enormous beetle land on my knee. Of course, I didn’t have my glasses on, or camera, to hand. However, while she was investigating the wood pile at the side of the house, and stopping a while to enjoy reflected heat from the rough casting I fetched them from indoors.
As soon as she was gone, I rummaged feverishly through my books trying to identify this magnificent animal. I was supposed to be packing and preparing for leaving home. I got as far as working out it was a longhorn beetle from the order of Coleoptera, and the Cerambycidae family, but I wanted to know the genus and species. I found out half an hour later by joining this Facebook group.
So, this large beetle with massively long antennae is from the sub-family Lepturinae, and is called Leptura quadrifasciata, or four-banded leptura. They are phytophagous meaning that they eat plant material. The adult beetle feeds on foliage and flowers but the larvae feed on wood plant tissue. This beetle might have been laying eggs in the woodpile.
Apiary Update.
This last week has been poor for foraging with high hot winds followed by days of heavy showers interspersed with burst of sunshine. I can tell when it’s about to rain even though the sky may be clear at the time I see the hive entrance black with returning bees. It’s rather like a swarm in reverse and they are tumbling over each other to get inside. This is my cue to collect in the washing from the line. And sure enough some few minutes later down it comes in heavy sheets—the rain.
So, lime has been in full flower but it is highly unlikely that much nectar will have come into the hives from that source as the hot winds will have dried it up. I checked on stores in all 6 colonies and 2 nuclei before leaving home for the best part of a week. It is amazing just how quickly they can run out of stores during our changeable weather even though so many great nectar sources are in full bloom.
Varroa levels have crept up in some colonies and I’m keen to deal with that early so that the winter bees produced from August onwards will have the best possible chance of survival. I’ve chosen to use formic acid which penetrates the cell and kills varroa under the cappings. This is the only varroacide that currently does this, and to date there has been no resistance observed. However, one downside is that it sometimes kills the queen, or prompts supercedure, so I am hedging my bets and not treating all the colonies just now, only the ones with the highest level of varroa. Best practice is to treat all colonies in the same apiary at the same time but I will be keeping a close eye on the others.
I use Mite Away Quick Strips. It is advisable to use the appropriate PPE for this job as the fumes are harmful to our lungs
https://www.thorne.co.uk/health-and-feeding/pests-diseases/pest-and-disease-varroa/varroa-chemical
We use icing sugar dusting if varroa become problematic one apiary has escaped it for four years now and the other has shown no sign so far this year though we are vigilant. I wonder if there is an advantage to accommodating early swarming to occur in colonies that have proven vulnerable in order to have a break in the brood cycle and to minimise drone rearing.
The Giant Hogweed is very impressive stuff and as gardens are packed with poisons and narcotics you could forgive it were it those, just not its fecundity.
Oh, I definitely believe that a swarming event causes the break in brood that hurts varroa. I’m not sure that that will minimise drone rearing though since drones are protandrous and, like many species, the males are mature before the females. I don’t do regular swarm inspections in spring till I see drones on the wing in the apiary. An interesting thing happened this season though. A long story ….. but, by mistake, I put frame of drone foundation in the brood box. So, unsurprisingly, it resulted in a steep rise of varroa in that colony. Because our weather has been so bad in July, the drones are being evicted early and so there are piles of these poor drones outside this hive. I used MAQS to deal with varroa (formic acid). I think icing sugar dusting alongside other methods is a good biotechnical measure against varroa.
Our weather has been similarly useless so far this summer and today’s inspection revealed very few drones and honey stores being used. I can’t bring myself to administer prophylactic treatments for varroa, I know it has been disastrous in the past but I have faith in their capacity to evolve. Easy for me to say though as they are not my livelihood.
I don’t think that prophylactic treatments are a good idea either so I check on varroa levels first.