The experiences and expertise which Californian scientific-beekeeper Randy Oliver shared were the undoubted highlight of The Beekeepers Conference in Whanganui, August 11-13. With three speaking slots, as well as Q&A sessions, the American doled out plenty of advice and information.
Oliver was quick to point out “all of this information is on my website”. Therefore, you are encouraged to visit www.scientificbeekeeping.com for more comprehensive explanations of the below titbits.
Takeaways from Randy Oliver at The Beekeepers Conference 2024
· The dedication of Oliver to not only seek answers to the many questions we have as beekeepers, but to go to the extensive lengths required to get them from trials in his thousands of California beehives, is inspiring. Over three days, the knowledge he has built up was frequently called upon whether he was on stage or in the audience, and his advice carried a high level of gravitas as it is so frequently backed by demonstratable “hard data”.
· “I’m a beekeeper info sceptic,” Oliver explained, saying people “just repeat things”… “Don’t believe any beekeeper who doesn’t say ‘I don’t know’ often.” … He also decried, “The worst thing that happened to beekeepers was the internet, because now every whack-a-doodle way of doing things is out there”.
Varroa Management Strategies
· “When you see a nice frame of sealed brood, that’s varroa reproduction taking place,” Oliver warned, saying that with a warming climate, California now has all-year-round brood in the hives and the mite increase is “off the charts”, requiring a minimum of four treatment rounds a year if undertaking almond pollination.
· And Oliver would know too, with his presentations littered with evidence of his years of data collection in chart form. Among the benefits of those charts is a greater understanding of the exponential growth of varroa populations. “It’s all based on your starting number. The greater the starting count the greater the growth and the steeper the growth curve”. Therefore, Oliver advises against waiting for mite counts to get high before treating. “It’s better to keep mite levels low all season – you get better bang for your buck.”
· On that note, Oliver quoted fellow American beekeeper Russell Heitlzam who says, “I’m not treating because I have high levels of mites, I’m treating because I don’t want to have high levels of mites”.
· The higher proportion of eight-day-old larvae to adult bees in a hive, the more efficient varroa are at reproducing. When is that? “just before swarm season” and therefore proactive control of mites earlier in the season leads to healthier bees and easier control later on.
· Oliver is a huge advocate of mite monitoring, preferring soapy washes of 300 bees per sample. His business undertakes thousands every season and it is nothing for a team of two or three staff to undertake 400 in an afternoon. They aim for a mite wash “per minute, per man” in their well-honed system, at a cost of about US$1.50 per.
· Time of year must be considered when assessing mite levels. Low mite counts in early spring – when capped brood is first present in abundance and thus when most mites have entered the brood and departed their phoretic state – can hide a larger concern, Oliver warns. One to two mites at this time of year, should be the treatment threshold.
· Regarding late season bee/mite drift between hives, aka ‘reinvasion’, Oliver had some choice words. “Man I have heard that a lot since I got here, without one piece of evidence … If you are blaming all your varroa problems on mite immigration, the data does not support it,” he says, having undertaken trials in his own apiaries where varroa-free hives were placed alongside, sacrificed, varroa-laded hives as the colonies collapsed. Almost half the hives maintained mite counts of zero. “Mite immigration is not universal … every hive is different”. “A drop from 95% treatment efficacy to 80% might still return you a 0 mite count off 300 bees, but the varroa mite growth is exponentially so much faster. That is why I am sceptical when Kiwi beekeepers blame reinvasion.”
· Oliver says a management practice that “revolutionised” their varroa control was splitting all their hives in late spring, following almond pollination, and putting a queen cell in the split. During the colony’s broodless period it is treated with an oxalic-acid dribble to greatly reduce the presence of phoretic varroa mites – which all should be when a colony is broodless.
· Varroa in America have been found to be 20 times more resistant to amitraz (the active compound in Apivar and Apitraz) than in the 1980s, Oliver reports. By continually using a highly-effective treatment, without rotation “you are running a breeding programme for resistant varroa” he warns Kiwi beekeepers, as the few surviving mites have a high level of resistance among what becomes a limited genetic pool. “Rotate your treatments”.
· One drone can have as many as seven varroa mites on it and thus, if included in the approximately 300 bees in a wash, drones can totally throw off results and should be avoided. “Too erratic”.
Selective Breeding for Varroa Resistance
· After about two decades of targeting breeding from colonies showing varroa resistance, Oliver says half of their hives no longer require any varroa treatment.
· “We select for resistance, not tolerance,” Oliver explained, saying decisions on what varroa resistant colonies remain in the breeding programme is made solely off mite counts during monitoring. “We don’t tell them how to do the job”. He further went on to explain that they are not searching for ‘VSH’ which results in non-reproductive mites, “whether the mites in the wash are reproductive or not, we don’t care. If they got there, they got there somehow and we don’t want them”.
· Oliver has a remote area in California where he struck up a relationship with the few neighbouring beekeepers to supply their queen stock to help control drone genetics in the area.
· “If you don’t already have resistant stock, you will need to bring it in”, Oliver said, but then emphasized the importance of sticking with the stock once the programme begins. “The grass isn’t greener”. Essential for Oliver’s programme was finding “Queen Zero”, that being the queen of a colony that routinely returned zero counts during mite washes.
· Traits of gentleness, above average honey production, and freedom from disease are prioritised, alongside zero mite counts. They like to get mite counts of zero per 300 bees sampled five times in a row, over numerous months, before grafting from a queen.
· “You do not need to kill a single mite to control varroa, you just need to stop them reproducing,” Oliver pointed out, saying cutting the usual reproduction rate of 1.45 in half “will solve your varroa problem”.
· Drone genetics have a two year lag as their gene alleles come from their grandparents, and this can make genetic gains in bee breeding slower than anticipated, Oliver warned.
· Having trialled taking samples from all frames in beehives, taking bee samples from the first frame adjacent to the brood provides the best colony “average” mite count, while greatly reducing the chance of collecting the queen, Oliver reported.
Ways to Use Natural Miticides
· Oliver says his beehives in California “have been off the pesticide treadmill since 2001”, instead relying on his varroa resistance breeding programme and a range of organic treatments – extensively trialled.
· “You guys are lucky as hell,” Oliver said of the “own use” clause in New Zealand’s laws surrounding use of compounds in beehives. In California, he must apply for and receive dispensation to use many organic varroa control products. “Your government is smart. They know you are all cowboys and are going to do it anyway, so they don’t make you criminals.”
· Oliver stressed the need to assess treatment success with mite washes post treatment.
· Thymol treatments “just kicked butt” in their operation and in some hives took mite counts of 70 per 300 bees down to almost none in 21 days. However, they should not be used in the presence of honey supers. Oliver soaks “acoustic soundboard” (with ‘Pinex’ being the likely equivalent in New Zealand) in thymol and places it on the top bars of the hive, with a spacer rim.
· Formic acid “gives colonies a fresh start” Oliver said, resulting in healthy looking brood. However, queens can be susceptible to it and the hot weather in California results in variable efficacy.
· Oxalic acid liquid “dribbles” are used during broodless periods by Oliver, but he warns against mixing the acid with sugar water as he believes the nurse bees eat it and feed it to larvae, damaging the young bees. Instead, he prefers a 5:95 glycerine: water solution.
· He prefers extended release oxalic acid treatments over vaporising which he deemed “way too much work” and, having trialled a variety of extended release mediums, he concludes that the ratio (himself preferring 1:1 acid: glycerine) is more important than the medium.
Nosema
· “There is zero evidence that either nosema ceranae or nosema apis causes dysentery. It is a myth. Dysentery will help spread nosema spores, but nosema does not cause it,” Oliver said.
· When testing for nosema – which Oliver does himself in the field under a microscope, having sampled bees – results should be taken from the total percentage of bees with spores present, not total spore count. “Spore counts mean almost nothing as a single bee can throw it out”.
· His observation is, when pollen is not coming into the hives, nosema disappears, as Oliver could not find it present in any high level in late summer, but could in spring.
· “Beekeepers are absolute suckers for snake oil’,” Oliver observed when discussing hive health products. “Ask, ‘where is the evidential hard data?’… paid testimonials are not hard data. If something really works, you will see multiple replicated data from multiple trials… it’s not that hard to run a field trial.”
