August 20, 2019
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Coffee Bean Borer Q&A

Questions that have been answered by Kona Coffee Farmers Association CBB expert researcher- Suzanne Shriner.
(Thank you Suzanne!)

10/03/11 Question: I heard that if the beetle is already in the center bean the fungi can’t get to it. The best time to spray is when the beetle is flying around.

Answer by Suzanne Shriner: Last week I recommended to a farmer friend that he spray soon.  His first round was at 20% with many of the floater beans fully eaten out by CBB.  To me, this indicated that he had several generations going forth and multiplying.  This is opposed to farms where most of the beans have only half-eaten or pinhole beans, which might indicate fly-in or reduced infestation rates.

It isn’t quite right when they say the fungus won’t make it to the middle of the bean.  According to the experts, the female sits in the entry hole to block access from other CBB or predators. If you have the wetting agent (Silwet/Widespread), it will be possible for the fungus to reach her.  Not always of course, some of it is luck of the spray angle and etc.  But if the female gets fungi’d, high odds that the larvae will pick it up from her as well.

As we harvest the beans, the beetle moves out of the cherry.  Some of these will be fertilized females.  Spraying now might minimize damage to the later rounds.

Evidence of fungus growth seems to depend on elevation and moisture.  At our makai farms we rarely ever see the white spike.  Just not humid enough, most of the time.  But we do see dead bugs after spraying.  So it’s working.  The white spike is a last phase of the fungus lifecycle and doesn’t necessarily indicate true effectiveness.

April 2011

Pick All green and cherry now even if you do not see any evidence of Cbb?

1) Do you have CBB on your farm?  If the answer is yes (because you had it last season), and you removed all the raisin at the end of your harvest, then you might leave the green and cherry as a barometer of current infestation.  just be sure to regularly inspect the beans as I have noted the transition happens rapidly.

If you had CBB and did not remove the raisin, then I recommend removal of all raisin and 2010 crop.  I did this on my heavily-infested makai farm and have seen a very low re-infestation rate so far.  I hope to keep it further in check with spraying.

2) What is your elevation?  If you still have a picking round or two because you are mauka, then you will have to evaluate what the best financial option.

Can Round-Up be combined with Botanigard…?

I have had many questions about the compability of Roundup/glyphosate with Botanigard.  I continue to tell people no.

I don’t make this decision lightly but I do it on the basis of the research I have found.  While true that glyphosate and Botanigard are compatible in a two-hour mix test, the greater issue is in spore growth over time.  Most research i’ve seen show that glyphosate (or perhaps the inert ingredients) will RETARD spore growth.  The following study was sponsored by Monsanto, so I believe is fairly objective in its results.

“Beauveria bassiana growth was inhibited by five of the seven glyphosate formulations (Table 2).
RoundUp Ready-To-Use, RoundUp Pro, RoundUp Ultra, and RoundUp Ultra RT had the strongest fungi-
cidal properties, inhibiting spore germination and mycelial growth…”

Fungicidal Effects of Glyphosate and Glyphosate Formulations on Four Species of Entomopathogenic Fungi W. E. Morjan, L. P. Pedigo, and L. C. Lewis

There is also the issue of water spray rates being much higher for Botanigard versus herbicide, which can be compensated for by concentration, of course.Each farmer will make the decision for themselves.  But as I am speaking to an industry, I must go with the conservative statement. I do not recommend mixing with glyphosate-based herbicides. Our coffee crops are too valuable to potentially jeopardize.