Conflicting Info re amount of HB Nematodes per acre and the frequency of application

Asked May 12, 2016, 6:48 PM EDT

Hi Marc,
Thank you for taking my questions... How many HB (cruisers) nematodes (to kill Japanese Beetle Larva) should be applied per acre?
Some suppliers say 50 million HB per acre, others say 500 million HB and some say 1 billion HB. We planted row middle grass late August 2015 in our 2.5 acre Organic Blueberry Orchard. Not too many beetles have made their way into the grass quiet yet, but we have supplied the local JB population with a place to lay their eggs and feed their young!
Also, some suppliers say apply nematodes in Spring and Mid-August (NEK of Vermont) Other suppliers say it is a waste of money and nematodes to apply in the spring because the Japanese Beetle larva is half adult and the HB nematode cannot eat it very well. What are your thoughts? Thanks, Sweet Seasons Farm

Caledonia County Vermont

4 Responses

Hello Sweet Seasons Farm
It sounds like you were engaged in a conversation with Marc, and I would like to send your current questions on to him. BUT, do you have the last name?
Was Marc an extension specialist in VT? Perhaps Mark Cannella in the Berlin office, Farm Business Management Specialist, 802-476-2003 ext. 207,
You should have a link to respond your notification email, or contact me directly.

I'm not certain. All I know is I had been reading responses to other questions asked by a person named: "Marc".

Hi Sweet Seasons,
Vern Grubinger, UVM Extension Vegetable and Berry specialist, put together some good Nematode information, with a section on application:

You may find some information on nematodes in the Tree Fruit - Terry Bradshaw is the tree fruit specialist, 802-922-2591

From this UMaine Extension Japanese Beetle fact sheet: "Japanese beetle white grub management efforts are most effective when control agents are in place when the white grubs are small and feeding in the turf root zone. In New England, beneficial nematodes (best application time: last three weeks of August) have been shown to be somewhat effective in managing white grubs, whereas milky spore has had spotty results and is not recommended."

You can search out info from Extension across the country:

You can reach Vern at 802-257-7967x303, though since he does not work with Apple growers, he is not likely to have direct experience.

Are you signed up to be on the Vermont Vegetable and Berry Growers Association Listserv? You could ask if anyone has first hand success. Sign up info is here - if you are not on the list, be aware that it is very active with a number of Q&A per day.

Thank you, Sue. I will contact Terry Bradshaw! :-)