Page 23 - Griffin Gazette Issue 1 - 2018

seem to be a tall order for the nematodes. Add to Nematodes are heavier than water, so without
that the fact they’re very susceptible to UV light, gentle circulation, they’ll quickly settle to the bottom
and the deck seems to be stacked against such of the stock tank or sprayer, leading to uneven
treatments being successful. distribution. Ideally, the nematode application
should begin as soon as they’re uniformly mixed
The pre-pupal and pupal stages of thrips are into the stock bucket.
sessile, meaning that they don’t move. Research
indicates that most of the pupation takes place Oxygen begins to be depleted in the stock tank
on the surface of the soil, even when flowers and can reach critical levels after an hour or so.
are present although it varies somewhat by Gentle bubbling of air through the stock tank can
ii
plant species. Soil is the natural habitat of the be used to keep the water oxygenated as well as
nematodes, so their longevity is much better when provide the gentle mixing required to keep the
compared to foliar treatments where they survive, nematodes in a uniform distribution throughout
at most, for a few hours. That combination would the tank. Dramm has an agitation/aeration bucket
seem to favor making soil applications to assist designed specifically for this use. Inventive growers
with thrips control rather than foliar applications. have also come up with remedies of their own. It’s
important not to supply so much air that vigorous
It’s possible that the growers who have been bubbling results in damage to the nematodes.
successful with foliar sprays of nematodes were (They shouldn’t feel like they’ve been through a
applying them with sufficient water volume that blender!) GGSPro can provide a bulletin that shows
nematodes were reaching the soil surface to one way to create a homemade bubbler. (See the
assist with control. Soil treatments also allow
for control of fungus gnat larvae, which is a very digital Gazette!)
important bonus. Recommended nematode application rates to
combat thrips pupae and fungus gnat larvae is 50
Tips for success with nematodes million per 1,100 ft². Applying 30 to 50 gallons per
Applying living organisms, such as beneficial 1,000 ft² is a good drench volume. Re-applications
nematodes, carry some extra considerations are generally made at 3-week intervals depending
when compared to a typical chemical treatment. on pest pressure. BASF offers a compatibility Dramm agitation/
In preparation for the application, make sure to guide showing which pesticides and adjuvants aeration bucket
remove injector and sprayer screens that are 50 can be safely tank-mixed with nematodes. (Check
mesh or smaller. That will ensure the nematodes the online bonus section for this chart.) GGSPro
pass through the irrigation system unimpeded.
recommends not tank-mixing the nematodes with
If a sprayer will be utilized in the application, keep any pesticides, but the table is useful for knowing
the pressure below 200 psi if possible, with 300 which pesticides can be applied over the top of the
psi being the maximum. After spraying, follow nematodes without harming them.
up immediately with enough water to rinse the S. feltiae can be an important part of Western flower Western Flower Thrips
nematodes down to the soil surface.
thrips control whether a biological or a traditional Application
Refrigerator storage temperatures are 38 to 40°F, chemical program is being employed. GGSPro is
so allow the nematode packages to come up to available to advise growers on options to control
room temperature before mixing with water. Ideal other life stages of thrips by either method.
water temperatures for mixing and applying are i Buitenhuis R, Shipp JL, 2005. Efficacy of entomopatho- How to Mix & Apply
60-75°F (16-26°C), quite a shock if the nematodes genic nematode Steinernema feltiae (Rhabditida: Stein- Nematodes
aren’t given a chance to acclimate. ernematidae) as influenced by Frankliniella occidentalis
(Thysanoptera: Thripidae) developmental stage and host
During warmer times of the year, the stock bucket plant stage, J Econ Entomol. Oct;98(5):1480-5.
can actually get too warm, which may decrease ii
Buitenhuis, R. and J.L. Shipp, 2008. Influence of plant
nematode viability. In that case, insert a cold pack species and plant growth stage on Frankliniella occi- Nematode
into the stock bucket to ensure that the water dentalis pupation behavior in greenhouse ornamentals. Compatibility
temperature stays within the ideal range. Journal of Applied Entomology132: 86-88

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