nematodes as a biologic control

On December 24, 2022, Atlanta experienced a historic single digit 8°F (-13.3°C) minimal temperature.  This cold snap turned green ground cover brown and likely pushed small hive beetles (SHB) deeper into hives and compost piles. 

My bee yard has high shade, good soil moisture, and summer soil temperatures for SHB reproduction.  I used biological control, Beneficial nematodes (Heterorhabditis Indica), to treat the soil for SHB larvae.   At dusk, I watered the liquid nematode suspension onto the soil.  Direct sunlight (UV light) is fatal to nematodes.

It's one thing to see and squash adult SHBs with my hive tool and another stranger thing to take a leap of faith releasing after dark 'The Smallest Show on Earth' -  Step Right Up! Step Right Up!

• Moved the insulated FedEx mailer with 2.5 million microscopic nematodes to the refrigerator. 
• Removed the leaf litter at the hive locations and then wet the soil.  
• The next step was washing nematodes from gel transport material - small gel pieces can clog the watering can.   I used a large strainer with a fine mesh to remove and rinse the numerous gel pieces.
• Added more water to the bucket and stirred it to keep the nematodes from settling to the bottom.
• At dusk, I watered the biologic control onto the soil.

beneficial nematodes

Beneficial nematodes (Heterorhabditis Indica) to treat the soil for SHB larvae arrived in an insulated FedEx mailer which I moved to the refrigerator.  As shown in side-by-side photos, I removed the leaf litter at backyard hive locations and then wet the soil - all strategies so the nematodes land on wet soil and not on top of leaf litter.

The next step was washing nematodes from gel transport material - small gel pieces can clog the watering can.   I followed the Southeastern Insectaries instructions which recommend using a tea strainer.   In hindsight, a larger strainer with a fine mesh is more desirable as the numerous gel pieces quickly overwhelmed the capacity of a typical tea strainer.

I added more water to the bucket, then stirred to keep nematodes from settling to the bottom.  Ultimately, I transferred the liquid to a watering can.   Direct sunlight (UV light) is fatal to nematodes, so one hour after dark I watered the liquid nematode suspension onto the soil - while wearing a head lamp.

small hive beetle larvae 2020

I lost one hive - small hive beetle (SHB) larvae ate their way through the comb and fermentation "slimed" the frames making them unfit for honey extraction.   As shown, I moved all boxes with frames away from the backyard hive locations for sky burial.  SHB arrived in south Georgia in 1999, subsequently SHB numbers can not be reduced to zero - they have become part of the beehive population.

To understand how bad things happen to good people - here I summarized an Australian agricultural pamphlet describing how to manage SHB.   For this lost hive, I've placed a check mark next to my summer 2020 beekeeping practice and observation:

• Minimize hive manipulations ✅
• Keep a high bee to comb ratio (aka maintain colonies with strong flight activity)
• Maintain good hygiene around the apiary ✅
• Avoid using combs/equipment that are infested with any stage of the SHB life cycle ✅

In comparison, a surviving joined stack of two hives has strong flight activity.   This joined stack consists of an overwintered hive on the bottom capped with an open Cloake Board and topped with a medium sized spring 2020 swarm capture.

As shown, the screened bottom board has fermented debris, SHB larvae and a few adult SHB.  I ordered beneficial nematodes (Heterorhabditis Indica) to treat the soil for SHB larvae. As described on the Southeastern Insecectories website, "Each SHB larvae killed by H.indica can cause reproduction of up to 20,000 more nematodes."