To Squish or Not to Squishin MD Veggie Gardens

June 2, 2021Patricia Lynch, Master GardenerMCP Community Garden, Liaison

• Special Thanks to:

Jon TraunfeldDirector

Home and Garden Information Center

Common biotic problems (excluding wildlife!)

• Flea beetle• Colorado Potato Beetle• Cabbage worms, multiple types• Harlequin Bugs• Cucumber beetle• Squash bug• Squash vine borer• Mexican bean beetle• Stink bugs, multiple types

Integrated Pest Management (IPM)

AKA--The Intelligent Person’s Method!Elements:• Examine both sides of plant leaves and stems• Physical and Biological Controls• Prevention Measures• Less Toxic Alternatives• Use of Organic Approved Pesticides only if

Absolutely Necessary

Physical ControlsFloating Row Cover

• Spun-bonded polyester; gauzy material. Draped over crop and secured to ground; leave slack to allow crop growth.

• Excludes pests, and increases crop growth in spring and fall by raising temp. and humidity.

• Can be re-used; must be removed before flowering of cross-pollinated crops (cukes, squash, etc.)

Tips for Using Row Covers

• Row covers come in different weight or thickness depending on purpose:– light weight is used to keep pests off plants. – Heavier weights to protect from frost and colder

temps for early Spring and/or Fall planting• Row covers don’t work if the pest is already

lurking– Inspect ALL seedlings and remove any pests BEFORE

using the row cover--store bought and home grown!– Install the row cover right away—before the pests

find your precious plants!

Flea Beetles, Row Covers Happy Eggplants!

Biological controls• Give mother nature a chance!

– Predators eat pests– Parasitoids lay their eggs on or in pests

Natural predators

SpiderLadybird beetle larvaAssassin bug

Hornworm parasitized by tiny Braconid wasps

Prevention• Use Bird and Bat Houses to reduce insects• Plant to attract beneficial insects and support

pollinators --mountain mint, anise hyssop, thyme, oregano, basil, dill, yarrow, aster, marigold, zinnia, alyssum, phlox, bee balm, milkweeds, butterfly weed, borage, salvias, lamb’s ear

Prevention

• Keep garden free of diseased plants/debris to limit hiding places for insect pests and slugs

• Time plantings to avoid peak insect infestations—plant early, plant late, plant multiple times

• Clear out dead plants, weeds, and debris at the end of the season to reduce over-wintering

• Try a cover crop to revitalize and protect soil

Organic Pesticides

• Products are labeled for Organic Gardening or OMRI Listed

• Products may be less toxic than other pesticides, but they ARE pesticides, and can cause harm

• Please note Organic, Natural, and Safe don’t necessarily mean the same things

• These products include things like insecticidal soap, Neem, Spinosad, Pyrethrum, Horticultural Oil, and Bt (Bacillus Thuringiensis)

More Organic Pesticide Info

• READ and FOLLOW all label directions—It’s the LAW!

• Chose the product based on the pest you have. Some work only if direct contact is made. Others only work on one stage of development. Some only work on specific pests—one product does NOT fit all!

• Wear protective clothing as specified on the label• Use only as directed

Colorado Potato Beetle

Organic Management

• Look at leaf undersides to find egg masses• Check all nightshade plants• Handpick, crush eggs• Use Row Cover whole season, pollination not

needed• Consider crop rotation and/or growing

nightshades every other year• Kaolin clay, Neem, pyrethrins, Spinosad

Cabbageworm Butterfly

Imported Cabbageworm

Photo: Whitney Cranshaw, Colorado State University Bugwood.org

Cabbageworm larva

Organic Management

• Remove all plant debris• Floating row cover prevents egg laying• Handpick larvae• Use Bt on younger caterpillars• Spinosad, Neem, and pyrethrum are

effective—apply as directed on label• Pollen-rich flowers attract predators and

they will reduce populations naturally

Harlequin Bug Life Stages

Organic management• Remove (chop and hot compost) all crop residues

immediately after.• Search out and manually crush eggs, nymphs, and

adults. • Floating row cover from transplant to harvest.• Spray nymphs with an pyrethrum + oil or neem +

oil (spray must contact bugs).• Mustard greens and Chinese cabbage are most

vulnerable crops.• This can become a major “community” pest

because Brassicaceae crops can be grown year-round.

Spotted cucumber beetle

Striped cucumber beetle

Bacterial Wilt Disease

bacterial ooze

Organic Management• Difficult to hand-pick; must be controlled

early in season.• Exclude with floating row cover until bloom• Protect plants prior to flowering with

organic insecticides (apply to both sides of leaves), Neem, pyrethrins, Spinosad.

• Seal up badly infested plants in plastic bag.• Plant late; plant multiple crops. • Select varieties resistant to cucumber wilt

and mosaic virus.

Squash bug

Eggs and immatures

Organic management• Remove plant debris to eliminate

overwintering sites.• Hand-pick adults and eggs; place wooden

boards next to plants. Check under boards in AM destroy nymphs or adults.

• Floating row cover from transplant to flower.• Plant late (mid-June) or plant a spring squash

trap crop.

Wilted squash- what could be wrong?

Squash vine borer

Organic management• Floating row cover from planting and anchor

firmly to prevent the SVB moth from entering. Keep covered until flowering.

• Wrap stems with aluminum foil collars, check regularly.

• Cut affected stem, remove or pierce larva/e.• Destroy all affected plants! Do not compost!• Practice crop rotation. Pupae overwinter in

soil.

Mexican bean beetle- “skeletonizer”

Mexican Bean Beetles

ating Mexican bean beetles

Organic Control

• Squish, squish, squish—adults, larvae, eggs• Use row covers as soon as you plant—remove

at flowering• Clean up garden debris• Remove infested plants, do not add to

compost or garden debris piles• Apply kaolin clay, Neem, pyreythrins, spinosad

Brown marmorated stink bug

Organic Management

• Found mostly on beans, corn, tomatoes, peas, peppers, squash.

• Use row cover beginning in spring.• Search for egg masses and crush. Handpick bugs.• Bugs hide or drop when startled. Knock into a

container with soapy water held underneath.Clean up plant debris after the season, especially crucifers and legumes. Tilling disrupts overwintering sites.

Organic Management

• A cloudy spot in fruit can be cut out and does not affect eating quality.

• Insecticidal soap or botanicals such as Neem or pyrethrum are only effective on young nymphs. Adults are resistant even to highly toxic insecticides.

• Thick organic mulch provides desirable habitat for stinkbugs. Consider removing mulch or using plastic, fabric or rolled paper mulch.

Resources

• Home and Garden Information Center. University of Maryland Extension http://extension.umd.edu/hgic

• The Vegetable Garden Pest Handbook by Susan Mulvihill. Quatro Publishing Group, April 2021

• Search Engine of your choice—Enter: Pests (or Diseases) of Name of Plant

More Resources

• Mac’s Field Guide: Bad/Good Garden Bugs of the Northeast: A Laminated Chart. The Mountaineers Books, 2000.

• Good Bug Bad Bug by Jessica Walliser. Spiral bound Field Guide. St Lynn’s Press, 2011.

• Your Smartphone—various apps—iNaturalist/seek, Picture This ($ 29.99/yr)

Thank You!

Q

Harlequin bug nymphs hatching from eggs

Predatory Stink Bug