Insects & Diseases
IPM Defined:

"IPM is a sustainable approach to
managing pests by combining
biological, cultural, physical and
chemical tools in a way that
minimizes economic, health, and
environmental risks."
IPM
Pest management, not eradication, is
the goal.
 Manage pests below the economic
threshold.

Economic Threshold
How would you define it?
 The point at which the disease or pest
infestation begins to diminish the quality
of the crop.

Economic Thresholds

Thresholds should be quantitative and
grower driven.
 For example, thresholds could be based on
the average number of pests per trap each
week.
 the percent of plants or leaves found to be
damaged or infested during visual
inspection.
 the number of pests dislodged per shake
sample.
Economic Threshold
80
Avoid exceeding economic
injury level
70
EIL
60
Apply controls
50
ET
40
Average
density
30
20
10
0
Time
Economic Thresholds
Vary depending upon the crop.
 Bacterial Leaf Spot on Poinsettia:

 Devastating!

Bacterial Leaf Spot on Greenhouse
Tomatoes:
 Not such a big deal. Why?

Insects & diseases on ornamental crops
grown in nurseries:
 Big deal? Yes or no?
Scouting and Record Keeping
Also called “monitoring’.
 Perform weekly.
 In greenhouses focus monitoring near
doorways, vents and fans.
 1 card per 1,000 square feet.

 Yellow: attracts most flying insects
 Blue: for thrips

Replace cards on a regular basis.
Cultural IPM Tactics
Sanitation

The goal of sanitation is to eliminate all
possible sources of the pest.
 weed removal inside and outside the
greenhouse.
○ grass flowering-increase in thrips population
 weed removal around nurseries.
 dispose of dead/diseased plants.
 In greenhouses:
○ quarantine infested plants in a separate room.
○ medium pasteurization (especially if it contains
soil).
○ algae control-fungus gnats.
Watering

Too much moisture:
 leaf diseases
 root rots
 fungus gnats
 algae

Too little moisture:
 stresses the plants and predisposes it to
disease
 hot, dry conditions favor spider mites
Temperature
Plants begin to stress at temperatures of
95 degrees F. and higher.
 Temperature fluctuations.

Growing Medium
Should have good aeration/drainage.
 Monitor EC.

Variety Selection
Choose insect/disease resistant
varieties.
 If possible, rotate crops.

Physical/Mechanical IPM Tactics
Insect Screening
Biological IPM Tactics

The use of living organisms to control
pests.
Lady Bugs
Parasitic Wasps
Predatory Mites
Chemical IPM Tactics:
Biorational Pesticides
 Conventional Pesticides

Biorational Pesticides:
Insecticidal Soaps
 Horticultural Oils
 Bacillus thuringiensis-bacteria
 Beauveria bassiana-fungus that infects
the chitin exoskeleton of many pests
 Diatomaceous Earth
 IGR’s

 kill insects by disrupting their development
Conventional Pesticides
Licensed Applicator
 WPS
 Re-entry Times
 Residue
 Resistance

 rotate between groups/active ingredients
Major Insect Pests of
Greenhouse-Grown Bedding
Plants:
Aphids
 Thrips
 Fungus Gnats
 Whiteflies
 Shore Flies
 Leafminers
 Mealybugs
 Spider Mites

Aphids
Immature & Adult
Greenhouse Thrips
Thrips Life-Cycle
Greenhouse
Whiteflies
Mealybug
excreting
honeydew
Two-spotted Spider Mite
Red Spider Mite
END