Greenhouse TPM/IPM Report
Central Maryland Research and Education Center
Ellicott City, Maryland
May 26, 2015
From: Stanton Gill, Extension Specialist – IPM for Greenhouse and Nurseries, Central Maryland Research and
Education Center, University of Maryland Extension
Karen Rane, Extension Specialist, Director of the Plant Diagnostic Clinic, University of Maryland Extension
Andrew Ristvey, Extension Specialist, Wye Research and Education Center, University of Maryland Extension
Suzanne Klick, Technician, CMREC, University of Maryland Extension
Four-Lined Plant Bugs Are Active in May
By: Stanton Gill, UME
Garden centers might receive questions about several insects
active in the landscape this week. Adults and nymphs
of four-lined plant bugs are feeding on perennials this
week. The four-lined plant bug uses its piercing/sucking
mouthparts to feed on chlorphyll. It secretes a toxin in its
saliva that causes white, dark, or translucent spots on the
leaves. If damage is extensive, these spots coalesce and
form large blotches. Heavy damage can cause leaves to
turn brown and drop.The damage is sometimes mistaken
for disease leaf spots. They feed on a wide range of annual
flowers and herbs, mainly in landscapes and nurseries. I have
Four-lined bug adults are yellowish green with
not seen them damaging plants in greenhouses. There is
four black stripes
one generation per year so damage only occurs early in the
season.
The four-lined plant bug nymphs are a bright red to orange color with black dots on the abdomen. Later instars
have black wing pads running halfway down the abdomen with a yellow stripe
on each wing pad; their wings are not fully developed yet. Adults are usually a greenish-yellow color with four
black strips running longitudinally down the wings.
Control: Acephate or acetamiprid. You can try neem products if they are still in the nymph stage.
Phlox Plant Bug
Another question for gardens center might be about phlox plant bugs
which are active on phlox in the landscape this week. Look for the yellow
stippling and distorted foliage caused by this feeding. The feeding by this
plant bug can stunt plants.
Control: For control, you can use any systemics (e.g. acephate).
These phlox plant bug nymphs are causing
distortion on plants and stippling damage on
the foliage
Insect Update
Up to now in the season we have mainly had reports of spider
mites and tarsenomeid mites as the major pests in greenhouses.
As the weather continues to warm up, thrips pressure is
increasing on greenhouse crops are still in the greenhouse at
this point, With many plants in bloom now, they are producing
plenty of pollen as a food source for thrips. Blue sticky cards
are good for detecting adult thrips in a greenhouse. Place at
least 3 – 4 cards in a 10,000 sq ft of growing area and check
the cards once a week to see if the population is going up or
down. Yellow sticky cards also work, but the blue ones are
more attractive to the adult thrips.
Control options: For low thrips populations, you can use
Azadirachtin (Aza-Direct, Azatin XL, Ecozin Plus, Ornazin,
Neemix) which will help keep them suppressed. The insect
growth regulator, Pedestal (Novaluron), is another good option
for immature stages of thrips and works best when populations With the warm temperatures, monitor crops
closely for thrips with sticky cards and
are relatively low. You can also use Pylon (Chlorfenapyr)
tap plants against white paper to dislodge
or Spirotetramat (Kontos). Kontos is both foliar and root
thrips from flowers and foliage
absorbed. Kontos is phloem-active, meaning users can
foliar-apply (spray) and be assured that the active ingredient
(spirotetramat) will move down in the plant. Growers can also soil drench Kontos, and because it is xylemactive, the active ingredient will move up systemically through the roots to the growing tips.
Upcoming Conferences
Greenhouse Tour and Picnic
June 25, 2015
Location: Greenstreet Growers, Lothian, MD
Alternative Crops for Greenhouse Production
Conference
August 5, 2015
Location: Brookside Gardens, Wheaton, MD
The information given herein is supplied with the understanding that no discrimination is intended
and no endorsement by University of Maryland Extension is implied.
Read labels carefully before applying any pesticides.
Photographs are by Suzanne Klick and Stanton Gill unless stated otherwise.
The University of Maryland Extension programs are open to any person and will not discriminate against anyone because of race, age, sex, color, sexual orientation,
physical or mental disability, religion, ancestry, national origin, marital status, genetic information, political affiliation, and gender identity or expression.