Vegetable Pest Management

1
Vegetable Pest Management Chuck Marr K-State
Research Extension Horticulture
2
Elements of vegetable pest control practices

• Proper identification of problem early enough to
  control
• Timing of control measures at critical time
• Thorough complete application- repeated if
  necessary

3
Alternative control measures
Effective alternatives Questionable

• Companion plantings
• Hand removal?
• Light traps

• Natural insecticides
• Biological pest control materials
• Row covers (exclusion)
• Soaps and oils
• Sulfur (not in heat)
• Rotation and intervals

4
IR-4 (Pesticides for Minor Use Crops)

• Critical crop pest control needs matched with
  potential pesticides
• Government grant sponsors field/residue testing
• Pesticide labels issued
• Traditional pest control materials
• Ultra-low application rate materials
• Bio-pesticides

5
Cabbage Worms

• Imported cabbage worm
• Cabbage looper
• Diamondback moth

All develop from eggs laid on underside of
cabbage leaves-developing into worms or larvae
that feed on leaves/heads.
6
(No Transcript)
7
Wetting agent Spreader-Sticker Liquid soap
8
Severe worm feeding reduce leaf area of
plant appear in heads or processed product
9
Corn Earworm

• (also known as the tomato fruitworm)
• Feeds on ends of sweetcorn ear
• When corn is husked, worms fall out
• No tolerance in processed product and very little
  tolerance in fresh product in grocery stores

10
Ear just visible
Silking
Mid silk
11
Silking to harvest 21 days (3 weeks) Silking
until silk start to dry at tips about 12-14 days
Silks fully extended and starting to dry at
tips Some varieties produce colored silks
12
Corn earworm moth is a night-flying dingy colored
moth that lays eggs on developing silks of
corn Larvae hatch, crawl down the silk and enter
the ear.
Prevailing weather patterns and air currents
cause waves or cycles of worms to fly into
our area. Typically about7-8 Waves or cycles/yr
13
Moths seek out some nice juicy silks and deposit
eggs.
Earworms are cannibalistic- multuple worms may
crawl into the ear but they eat each other so
only one worm remains.
14
As ear develops, silks extend or grow-exposing
new silks each day. Repeated insecticide
applications during silking- every 2-3 days until
silks start to dry (about 12-14 days into ear
development)
21 days from silking to harvest
Silking
Silks Start to Dry
Harvest
15
Monitoring earworm flights using a phermone lure
inside a sticky or cone trap. Male moths fly
up into cone made of netted material-caught in
the top chamber. Counted each day to monitor
flights.
16
Phermone lure attached to a delta sticky trap.
Folded to protect it from rain, dust and other
contaminants.
17
Tomato Disease Problems

• Fusarium wilt races 1,2 (and now 3)
• Leaf blight
• Septoria leaf spot
• Early blight
• Tomato spotted wilt virus

18
Fusarium wilt in tomato. No known control.
Persists for 8-12 years. There are 2 strains or
races F1 and F2. Need both resistance (A new
strain F3 has been discovered in the deep south)
19
Fusarium wilt in tomatoes

• Specific to tomatoes (Fusarium oxysporum
  lycopersicii)
• No known control
• Resistance in varieties
• V verticillium wilt
• F1,2fusarium wilt
• Nnematodes

20
Leaf blight (Early Blight and Septoria Leaf Spot)
is a different story. There is some resistance
available but hasnt proven to be very effective
in the field. Both are foliar fungus
diseases-spores develop on leaves and dont enter
the roots of the plant.
21
Tomato Spotted Wilt (TSW) Virus Stunted plants,
purplish color. Mottled, marbled fruit Spread by
western flower thrips-primarily in greenhouse or
transplants.
22
Mites (Spider Mites) Build up in hot, dry
conditions Small- on undersides of leaves
23
When severe, may see webbing on leaves.
Often confused with heat or drought stress.
Plants seem to fade away.
24
Dealing with mites

• Develop in spots or areas in the field/garden
• Control early
• Miticides
• Kelthane
• Dicofol (Cygon)
• Soaps (multiple applications)
• Sevin will cause buildup (kills predatory mites)

25
Vine Crops

• Cucumber
• Muskmelon
• Watermelon
• Pumpkin
• Squash
• Gourds

All produce a similar flavor compound
cucurbitacin. Attracts certain insects. Share
some common disease and insect problems.
26
Powdery Mildew Reduce yields 30-50
Difficult to control
Resistance now available in a few varieties of
pumpkins. Strong resistance in cucumbers and
muskmelon. Watermelon doesnt get.
Resistant Susceptible
27
Begins about 2 weeks after full vine cover-
usually 7-14th of August.
Resistance available in Cucumber
(strong) Muskmelon (strong) Pumpkin
(some) Watermelon (dont get) Squash (very
sporadic)
28
Bacterial wilt (cucumber and muskmelon) Bacteria
carried by cucumber beetle. Injected into plants.
Develops in vascular tissues-plugging the stems.
29
Fusarium wilt or blight in pumpkins
Pumpkins go out fairly early in season Dark
discoloration in stem
Long (3 yr) rotations and avoid root injury or
wet spots
30
Squash bugs- a grey shield-shaped bug that sucks
juices from the plant and releases a toxin that
causes wilting and death.
31
(No Transcript)
32
(No Transcript)
33
Squash Bug Population Dynamics

• Overwinter as adults
• Begin to lay eggs in late May 1 adult
• First generation mid June-July 500-600 adults
• Second generation lay eggs
• Second generation mid Sept-Oct 62,000 adults

34
Strategies for Squash Bug Control

• Reduce overwintering adults (hibernation places)
• Spray only after the hatch
• Control in 1st generation
• Remove vines as soon as fruit are mature
• Vine removal prevents overwintering and removes
  hibernation places

35
Microdochium Blight
First appeared in the mid 97s in eastern and
midwest states Typical fungicides controls dont
work very well.
Lesions on fruit and stem
36
Pumpkin Yellows or Yellow Stem-first seen in
2000
No brown discoloration in stem. Plugging of
phloem conducting cells in root. Little known at
present-suspected carrier are squash bugs.
37
Information from K-State Research and Extension

• http//www.oznet.ksu.edu/horticulture
• Pest Control in Vegetable Gardens
• Alternative Pest Control Measures in Gardens
• Common Horticultural Plant Problems (single page
  fact sheets)

38
Kansas State Research Extension
Knowledge for Life