This topic contains 6 replies, has 2 voices, and was last updated by Greg Garriss 4 years, 2 months ago.
April 28, 2013 at 10:45 am #31901
We are having excellent results with pyrethrin. We’re seeing kill rates of 70% to 100% depending on the application mixture. It seems to be a great solution for knockdown and hot-spot management.
It’s still early season, but we were dismayed to note that after doing the 30 Trees, we had an average infestation rate of 10% on one of our farms, with hot spots topping at 50%. This was not acceptable, and left unchecked, would lead to a crop loss situation. Andrea at CTAHR mentioned that they had done research in the lab with CBB and EverGreen 6% (OMRI certified and labeled for coffee). We decided to give it a try.
We used the Pyronyl 6% product (labeled for coffee), with the Widespread Max spreader. The first mix rate we used was approximately 8 oz per acre, which gave us the 70% kill. When we boosted the rate to 15 oz of Pyronol per acre, we found no live beetles left behind. Even a few in the CD position, inside the bean. We spray with a powered pump and drag hose, but a backpack sprayer would be sufficient. AS WITH ALL PRODUCTS, DIRECT BEETLE CONTACT IS VITAL. The higher the pressure, the more you shake the beans, “bother” the beetles and force them to back out of their holes and contact the pesticide.
The products are expensive, at $125 for 32 oz of Pyronol. We’ll be playing with the mixture rate over time to try and find the optimal oz/acre ratio for our farm. There is no residual, so it is a one-time kill, that is gone . We are mixing the Pyronyl with the Surround WP clay product. The clay serves as a long-term repellent. It is cheap, at under $15 an acre or so, and studies show it may be a yield-booster as well.
I would not recommend mixing either with the fungus. Pyrethrin products will also kill your beneficials so use them with restraint. For this reason, I would refrain from spraying them on the soil.
It remains to be seen whether this, or any product, is truly useful once the majority of beetle have moved inside the bean to the CD position. At this moment in the season, the vulnerability is high. I still believe the fungus is an effective long-term kill as it has a residual factor after the worker has left the field. However, for high infestations, this might be a more effective tool for immediate results.
As always, ready the label and wear the proper protection.April 28, 2013 at 8:04 pm #32044
Had done the same test to 1 acre this week: 15 oz of Pyrethrin per acre with 30 gal of water, + 15 oz of Widespread Silicone spreader. Two days later I am hard pressed to find a live beetle and it’s a glimmer of hope to have a decent harvest again!
A large field study is currently run by UH Manoa in conjunction with the Universities of Puerto Rico and Princeton/Rutgers, but the results will not be out till the end of 2014.
Pyrethrin is the oil of chrysanthemum flowers, and is allowed on coffee. There’s one with a lower percentage available for organic farms (Pyrethroid is the synthetic version of pyrethrin and is NOT ALLOWED on coffee!). In addition there’s Piperonyl butoxide added, so the insect can not break the pyrethrin down and get immune easily. You may know this product combo from flea shampoo for dogs or lice shampoo for kids.
Be careful with handling and applying because pyrethrin is a real broadspectrum insecticide, albeit one of the weakest ones available. It does kill bees and other beneficial insects, so please spray only when nothing is flowering. Don’t spray around your koi or tilapia pond either. Using beauveria bassiana and pyrethrin alternating might be an ecologically more sound route to go once we get the CBB onslaught under control.
Use a real breathing respirator, not just the paper protector. Dress in long sleeves, rubber gloves, hat, eye protector, or even a tyvek suit when spraying. Better safe than sorry.April 29, 2013 at 7:25 am #32204
I saw similar infestation numbers of my larger beans early last week. It appears to me that my first round of Botanigard spraying (32oz/acre, late Feb due to 1st week of Jan flowering) had almost zero effect. For whatever reason (probably lack of rain) the fungus didn’t take. I had sprayed Botanigard 2 subsequent times (3/25 – 16oz/acre, 4/11 – 16oz/acre). It appears that the fungus has actually started working. While collecting infested beans I am seeing near 100% kill of any beetle in AB position and roughly 80% kill in CD position. It is difficult to see the white “spike” of fungus for AB position beetles, but if they are gently flicked out I can see the white on their head. Beetles have not entered the actual bean yet (I am at about 100 days post flowering), so there doesn’t appear to be any reproduction occurring inside the beans yet.
Pyrethrin/Pyrethrum may be a good tool to start with especially for farms with early flowering that will have larger beans developed during the drier months.
I encourage anybody that had flowering earlier than Feb to check their beans carefully! We are looking at roughly 4 months before harvest season. Any infestation now could easily spin out of control if left unchecked.April 29, 2013 at 7:51 am #32208
I’ve been asked to remind people not to spray when open flowers are on the branches and bees are in the field. This will kill bees in the same time window as it will kill CBB. Also, watch drift if you have hives in the area.
However, unlike imidacloprid/Provado, it does not have a residual carryover. If you spray today, and flowers open tomorrow, the pyrethrin will not kill the bees.May 2, 2013 at 7:46 am #33065
Peter Van Dyke
Suzanne, when you mix the pyronyl with Surround, are you using both Widespread Max and Nufilm?
I was wondering about using Botanigard and Surround together in the same mix (without the pyronyl), and whether the two surfactants are compatible. Thanks!May 9, 2013 at 11:51 am #34657
I am not using the Nufilm, simply because it wasn’t in stock when I bought the Surround. So just a single surfactant. We started with the Widespread Max, and then switched over to Activator 90 (primarily because of cost). The Activator 90 seems to work better with the application of the clay product but it did seem to reduce our kill rate with the Pyronyl. Hard to know for sure as we have a lot of variables in the mix as we work out an efficient spraying system.
We are NOT spraying Botanigard with the clay. Our sprayer rig circulates water through the pump to keep the clay agitated and the water gets quite warm. I am concerned about viability of the spores with the heat. The clay is also a dessicant and I am not sure if spraying both together would dry out the fungus too fast. It would probably be fine (CTAHR research sprayed both with good results, but not at the same time). Definitely keep an eye on your kill rate if you choose to mix. And report back!May 31, 2013 at 6:17 am #40571
As a related aside, how rigorously is everyone cleaning their tanks between spray applications ( fungus vs pesticides,etc…)? I’ve been using separate backpack sprayers for biologicals vs toxins but just bought a powered tank sprayer and am considering getting a swap tank to do the same.
I’m also curious to hear about spray methods. I considered the Stihl SR but after walking around wearing one, it seems top heavy for my terrain and height. I invested in a hose sprayer instead.
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