Page 19 - Griffin Gazette Issue 1 - 2019
P. 19

CEA CROPS                         CHEMICAL                          BCA OPTION FOR

            SUSCEPTIBLE TO                    CONTROL OPTIONS                   ROOT APHIDS

            ROOT APHIDS                       Successful treatment of root aphids   The soil predatory insect Atheta coriaria,
                                              in CEA production systems requires   or rove beetle, is known to prey on root
            Root aphids can infest hydroponic   attention to a few factors. Drenching   aphids, but the level of control has not
            lettuce crops, spinach, basil, cannabis   to control pests below the soil line   been determined by research. Rove
            and other herbs. Different species   is a method that involves thorough   beetle are recognized predators of
            occur on the different CEA crops.   saturation of insecticide into the   fungus gnats, thrips pupae and shorefly
            Some common management strategies   substrate. Insecticides should be   larvae. Rove beetles are nocturnal; adults
            apply to all crops:               drenched on moist media to optimize   fly and the larvae are active and mobile.

            1. Scouting is critical for early detection   chemical penetration. Insecticide   Contrary to popular belief, there are no
            (see digital Gazette for scouting tips)  drench options are very limited   known beneficial, entomopathogenic
                                              in hydroponics, deep water float
            2. It is best to remove severely infested   beds, ebb and flow systems, as few   nematodes that will parasitize
            plants from production            products are properly labeled for   root aphids.
            3. Treatment should continue until the   use in these systems. The simplest   SUCCESSFUL
            pest is no longer detected        option to manage root aphids in
                                              hydroponics would be to drench in
            The most common type of root aphid   the liner stage, prior to moving the   MANAGEMENT OF
            found in lettuce is the lettuce root  aphid,   crop to the recirculating system. For
            Pemphigus bursarius. They're found in   cannabis, options can be even more   ROOT APHIDS IN
            clustered groups and distinguished from   limited;  follow recommendations   CEA CROPS
            other root aphids by short antennae   from your state. Some states allow
            and undeveloped cornicles. Their waxy   the use of EPA-registered products   Discovering root aphids can be
            coating can limit pesticide efficacy.   while other states only allow the   discouraging for growers due to
            Pemphigus root aphids can also infest   use of 25(b) products. Keep in mind   challenges in achieving control. Scouting
            herbs. Regardless of  crop, infested   that 25(b) products are often less   is key to catching problems early. If you
            plants will wilt during the day. Watch for   effective compared to EPA-registered   discover root aphids, take quick action
            yellowing and stunted leaves, stunted   pesticides.                 to discard highly infested plants and
            plants and malformed heads. Extremely   Altus (flupyradifurone): May be applied   determine the extent of the infestation.
            high  populations  can  cause  plant   as a drench to cucumbers, lettuce,   Remember to always read and follow the
            death; discard heavily infested plants.   peppers and tomatoes.     product label, especially when it comes
            If possible, cultivate root aphid resistant                         to treating edibles and cannabis crops.
            lettuce varieties.                Ancora* (Isaria fumosorosea Apopka
                                              Strain 97): Naturally occurring fungus
            The rice root aphid,  Rhapalosiphum   for drench application to CEA crops.
            rufiabdominale, occurs in cannabis   Repeat applications at 3-10 day    More to see online
            crops. Rice root aphids are olive-green   intervals. Most effective when relative   See our digital Gazette for more
            with  a  relatively  round  body.  Wingless   humidity is 80% or higher for 8-10   information on root aphids.
            forms develop on roots and survive in   hours. OMRI.
            all types of substrate. Offspring mature
            in about 9-10 days. The adults can live   BotaniGard 22WP* (Beauveria
            for a month producing several offspring   bassiana Strain GHA): Naturally
            daily at 73°F. In cannabis, root aphids   occurring fungus for use as drench on
            are often detected when plants show   vegetable crops in greenhouses and
            chlorosis (yellowing of the leaves) or   outdoor production.
            stunting. Growers sometimes mistake   AzaGuard (azadirachtin)*: Plant
            root aphid infestation for nutrient   derived, insect growth regulator for use
            imbalance. If you suspect root aphids,   as a drench. OMRI.
            carefully scout the root system.
                                              Azatin O (azadirachtin)*: Plant derived
                                              insect growth regulator. OMRI.
                                              * Allowed on cannabis in some states.
                                              Check your state’s approved list of
                                              active ingredients for cannabis.
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