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Pesticides And Whitefly How Can I Tell If Theyʼre Dead Pest by amberp


									BIO BUZZ
                                                                                           ISSUE 27 October
                                                                                          A GROWERS
                                                                                         REFERENCE TO

      Pesticides And Whitefly:                                                      From the Bugs
   How Can I Tell If Theyʼre Dead?                                                   Eye View…
    Evaluation of IPM methods has always been part of our Biological               Have a look at some of the insects
and Scouting Service. Part of evaluation is to check on the percent kill       in the greenhouse and you’ll find
after a pesticide application. Cleanup of whiteflies has already started at     some interesting fungi that are
some farms; heavy pressure from outside over the past few weeks has            naturally occurring, but are not
overwhelmed some Biological programs and before any honeydew                   considered diseases; at least of plants
starts there is going to be some spraying.                                     anyway. They are Entomopathogenic
    The adult whitefly is mobile, so it’s obvious what to look for after a      fungi, or Insect-pathogenic. They feed
pesticide application – a carcass. The first instar larva is semi-mobile and    on various components of the insect
can be flipped over on their backs                                              body and are spread mechanically
to see if the legs are still moving.                                           from insect to insect. They are
Note that it takes a steady hand                                               commercially available in other
and 40x magnification to try this.                                              countries (ex Beauvaria bassiana) for
Or you can wait and see if it                                          Dead    insect control. They are usually
shrivels up in a few days. Some                                                prevalent when there is consistently
of the larger larvae will turn a                                               high humidity and a low incidence of
brownish colour as well as                                       Alive         fungicide sprays.
shrivel up.

                                              Alive vs. Dead Whiteflies

 Pest Alert: Diapausing Spider Mites
    As of September 16, 2005, orange coloured two-spotted spider mites
have been sited at a cucumber greenhouse. Since then, there have been
a few more noticed, but the percentage is still low as of the last week of
September. The percent of adult females that will go into diapause will
continue to increase as the daylength shortens. We suggest that now is
the time to clean up mites to prevent overwintering and early problems
next year. Note that once mites have found shelter for overwintering, it’s
almost impossible to eliminate them with chemical means.

                                               Another Way
                                                  We Are
                                             Helping You Grow

                                                                                       Fungal Pathogen On An Insect
50 Hazelton St., Leamington, ON, N8H 3W1                        519-326-9037
       Out And About In Southwestern Ontario
All Crops:
    • Cabbage looper moths are still in abundance. The influx from outside should slow now that the vents are
      not open continuously. Eggs and larvae are still a concern.
    • Spider mites have started to go into diapause.
    • Heavy whitefly pressure from outside has led to abundant larvae and hot spots starting despite very
      effective biological programs.
    • Russet mites have increased significantly at some farms. This is mainly due to mites that have spread to
      new plants and are now showing damage.
    • Bacterial canker continues to spread. Even though it’s near the end of the growing season, it’s still
      important to remove infected plants.
    • Pepino Mosaic Virus continues to show up at more farms. Yellow spots, mosaic patterns on leaves and
      some “bleached” calyxes are more evident as the daylength decreases.
    • Aphids in small numbers are present.
    • Another round of powdery mildew has started at some farms.
    • Cucumber Mosaic Virus (CMV) and other viruses continue to be detected, especially as picking starts. This
      goes hand in hand with the increase in detection of new Melon aphid populations and mechanical
      transmission of existing infected plants. Any plants
      showing fruit with viral symptoms should be removed.
    • Cucumber beetles, both spotted and striped, are
      present in limited numbers. Note they can spread
      Bacterial Wilt and CMV.
    • Downy mildew has again been detected at
      quite a few farms. Wet, cold conditions are
      perfect for infection and establishment.
                                                                          Downy Mildew On A Cucumber Plant
    • Powdery mildew has been detected at a few farms.
    • Generally, thrips have been under control due to high populations of Degenerans and a new surge of
      Cucumeris in the past month.
    • Broad mites have continued to do some limited damage to fruit at almost all pepper greenhouses.
      Workers should try to avoid touching plants with symptoms as the mites can be spread on clothes and
      hands. Note that the new population increase of Cucumeris has helped with the Broad mites. We are finding
      good numbers of Cucumeris under the calyx feeding on Broad mites. Unfortunately the damage inflicted by
      just a few Broad mites (i.e. scabbing of the shoulder) can prevent marketability of the fruit.

The Ever Present Chickweed
    Everyone has it; everyone tries to get rid of it; everyone pays for it. This
common little weed may start out small, but it can become a tangled mess of
vine-like growth. Chickweed (Stellaria sp.) can reproduce by seeds and by
sending out roots at nodes. It’s quite a marvel of science. It’s also costing you
money. Chickweed is host for major insect pests (Lygus, spider mites, whitefly,
thrips, and aphids) and diseases like Cucumber Mosaic Virus (CMV), Impatiens
Necrotic Spot Virus (INSV) and Tomato Spotted Wilt Virus (TSWV)1. Cleanup
should include pulling of all weeds now. Diligence is certainly needed for this
one in particular. 1 PEI Agriculture, Fisheries, and Aquaculture Government
Publication 1400A; BC Ministry of Agriculture, Food and Fisheries website.

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