Page 20 - Griffin Gazette Spring 2017

IPM INSECT AND MITE SCOUTING
FOR GREENHOUSES
Joanne Lutz, GGSPro Technical Support Specialist
Numerous benefits can be realized by setting up an Integrated Pest
Management (IPM) scouting program. One goal is risk mitigation.
Insects and diseases can dramatically reduce a plant’s quality
and market value. Cultural and nutritional practices also influence
a plant’s susceptibility to pest attack and its ability to fend off
those attacks. Before you grow any crop, educate yourself on
the ideal growing conditions, irrigation and fertility requirements.
Be aware of potential pests and be prepared in advance for how
you’ll respond if trouble starts. Scouting requires time, and time
is money, so prioritize those crops that need more attention
than others.
Another benefit of IPM is to optimize pest control in an economically,
socially and ecologically sound way. Early detection of pests allows
for greater use of cultural and biological control measures. It is
through weekly scouting, good record keeping and treatment
evaluation that you’ll learn how to quickly identify pest problems
and make effective control decisions.
A motivated and dedicated person is needed to take ownership of
the IPM scouting program. Whether it is dedicated employees or
professional IPM scouts, their top priority should be scouting for
early detection of pests. Scouting involves inspecting the crop for
eggs and all life stages, as well as determining if beneficial insects or
mites are present. After the scouting is completed, the information
must then be formalized and recorded to provide the grower with
a clear, accurate picture of what, where and how many pests are
present. Lastly, an informed decision can
be made to treat the predominant life
stage present.
Various methods can be employed
to help growers identify changes in
pest populations. The most common
approaches are explained in detail below:
IPM scout
1) Install yellow or blue sticky cards
2) Whole-plant inspections
3) The “beat test”
4) Indicator/trap plants
5) Potato discs
Sticky cards are
used to monitor flying
insects such as thrips,
whitefly, fungus gnats,
shoreflies, winged
aphids and several
beneficial insects.
The most important
component of using
sticky cards is that
Yellow sticky card they be examined and
changed each week
to provide you with
up-to-date information. Cards allowed to stay in place for weeks
or longer yield little useful information. Place cards at 1-2/1,000 sq.
ft. for most crops and 2-4/1,000 sq. ft. for highly sensitive crops.
Place cards near vent openings and attach them so the bottom 1/3
Bonus Digital Content
of the card is in the crop canopy. Attach cards on bamboo stakes
using clothespins and place them vertically in the crop. Don’t forget
to number and date each card and location. This will help when
transferring the information onto data sheets and assist in tracking
pest population trends. Be sure to also utilize both sides of cards,
to determine directional movement of flying insects.
Remember, insects caught on sticky cards may look different than
living insects. A good reference picture ID sheet is available from
GGSPro to assist those learning to ID the primary insects caught
on sticky cards. Sticky cards can be messy to handle but by storing
these cards in the refrigerator, makes them easier to handle. When
it’s time to take counts from the cards, stretching plastic wrap over
the card will allow you to get close with a hand lens without getting
stuck to the card.
During whole-plant inspections, a
common rule of thumb is to inspect
10-20 plants per 1,000 sq. ft., walking
down an aisle in a zig-zag pattern. Not
all pests will be found equally through a
crop, so target inspections to examine
Plant inspection plants in the beginning, middle and end
using OptiVisor of a bench; along the aisle ways and from
the middle of the bench. Pick up at least
3 plants from each bench and examine
them plant starting at the crown. Inspect the entire foliage canopy;
examine both leaf surfaces, growing tips, buds and blooms. Include
an examination of the root zone in your routine for soil dwelling
insects and mites. Use a 16X hand lens or OptiVisor to assist in
identification of immature insects and/or mites. If identification on
the spot is not possible, collect a sample for further investigation.
Digital images can be saved to help in future diagnostic work.
During this visual inspection, think carefully about what a normal,
healthy plant looks like. Take notice if there is a problem and note
any specific symptoms or signs visible. Observe if there’s an overall
injury pattern and what portion of the plant is affected.
A beating tray, which is a piece of white
paper on a clip board, can be used to help
identify and quantify insects. Gently tap
the plants’ foliage with your hand over the
beating tray to dislodge any insects and
Beating tray mites present. Then lightly blow any debris
off the paper to leave behind the insects to
identify. The most common insects found using the beat test are
aphids, spider mites and thrips.
Aphids can range in color from green, light yellowish green,
orange, reddish-brown, pink to red. They have pear-shaped soft
bodies with two (2) cornicles (tailpipes) at the rear abdomen. The
legs and antennae are typically long and winged or wingless forms
may be present.
Wingless melon Winged
aphid aphid