Page 23 - Griffin Gazette Issue 1 - 2018
P. 23

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
            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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