avoid the tomato blues jon traunfeld jont@umd.edu

Avoid the Tomato Blues

Jon Traunfeldjont@umd.edu

College ofAgriculture and Natural Resources

Isn’t six months enough?

• With planning and not that much more effort• Harvest up to 10 or more months in MD• Increase variety and flavor

Tomato (Solanum lycopersicum)• Self-pollinating, tender herbaceous perennial;

produced as an annual crop around the world.• Fruit is 95% water; flavor determined by free

sugars and acids, texture and growing conditions.• Optimal growth and development occurs when

mean daily temperature is 70-75 degrees F.; growth stops below 50 degrees F. Flowers and fruits may drop when day temperatures >90 degrees F. and night temperatures >75 degrees F.

• Produces adventitious roots along stem.• Growth habits vary –determinate, indeterminate,

patio, jointless.• “What’s the best tomato?” They all grow well in

MD!

Tomato is tops!

• 2001-2013 HGIC answered 1765 e-mail vegetable questions; 38% were for tomato.

– Vegetable abiotic plant problems: 53% tomato– Vegetable disease problems: 62% tomato– Vegetable insect problems: 30% tomato– Vegetable weed problems: 11% tomato

Some IPM tips…

• Prevent problems and increase satisfaction by picking at breaker to pink stage. Ripen indoors unrefrigerated.

• People don’t notice the start of foliar diseases.• “Wilt” (loss of turgor) is a misused descriptor.• Don’t suspect late blight unless warranted.• Disease resistance is variable (field vs. genetic).• Is it ok to plant in the same location? (common

question)

Pick these…

Tomato plant & pest problems that cause greatest yield loss

• Arthropods- spider mites, stink bugs• Diseases- foliar leaf blights (early blight,

Septoria, gray leaf spot), late blight, fusarium wilt

• Wildlife- mainly deer; also groundhog, squirrel• Abiotic- poor growing conditions, climate

change, blossom-end rot, catfacing, cracks/splits, pithiness

INSECTS AND MITES

Some effective organic insecticides

• Pyrethrins- controls or suppresses a wide range of insects (Pyganic- 1.4%)

• Neem extract – suppresses beetles and caterpillars

• Neem oil- insecticide and preventative fungicide

• Spinosad- controls beetles, caterpillars, flies, thrips

Some effective organic insecticides (cont.)

• Bacillus thuringiensis- controls young caterpillars; suppresses large caterpillars

• Surround- controls aphids, mites, caterpillars; suppresses bugs

• Hort oil- controls aphids, mites, soft-bodied immatures

• Insecticidal soap- suppresses aphids, mites, soft-bodied immatures

Lady bird beetles chow down on aphids

Tobacco hornworm

I’m feeling sluggish these days… and what’s with these hitchhikers?

The braconid wasps win!

Photo: Rosemary Noble

Brown and green stink bug (native) and fruit injury

Brown marmorated stink bug (BMSB)

Photo courtesy: Susan Levi-Goerlich Photo courtesy: Jane Hayes

Eggplant leaves coated with Surround (kaolin clay)

Surround- kaolin clay

• 2006 research demonstrated significant flea beetle suppression in eggplant- may be effective against other pests.

• About $1 per lb. Rate: 1 cup/1 qt. water.• Spray when leaves are dry. Apply thoroughly to all

leaf surfaces. • Maintain white film coating on leaves; may take 2-3

applications. Re-apply if rainfall washes off white coating.

• Can be used up to the date of harvest.

‘Juliet’ has tough skin- suffers less BMSB feeding

Is it a problem? What can be done?

Climbing cutworm

Corn earworm a.k.a tomato fruitworm

Usually enter at stem end

Larvae mine and fold leaves and infest fruits.

Tomato pinworm

Spider mites love it hot and dry

Spider mites

Spider Mites• 8 legged, non-insect; active on leaf

undersides. Two-spotted and European red are primary pest species.

• Sucking mouthparts produce “stipples”; tiny bleached areas on leaf surface; leaves yellow and die

• Webbing is a sign of severe infestation • Wide host range; many vegetable plants• Thrive in hot, dry weather• Many quick generations each year

Organic Management

• Mites like it hot, dry, and dusty. Hose off plants to dislodge and annoy mites.

• Horticulural oil and insecticidal soap is most effective on eggs. May be used if leaves are not too damaged or hot to tolerate it.

• Excessive nitrogen fertilization increases mites• Mites will migrate from neighboring weeds, so

keep weeds supressed. Clean up garden residues.

PLANT DISEASES

Cultural control strategies• Grow resistant varieties.• Clean up and compost plant debris at end

of season.• Prune out injury; bag up badly infested

plants.• Plant lots of flowering plants to attract

beneficial insects.

Disease ID codes help you select resistant hybrid varieties

Totally Tomatoes

Early blight (fungal disease)- tomato

Advanced symptoms of early blight

Early blight- Alternaria solani• Principal foliar disease of tomato; also attacks

potato, eggplant; a cosmopolitan pathogen.• Splashes up to lower leaves and progresses up

plant; often appears with other leaf spot diseases.• First symptom is irregular brown lesions with

bulls-eye pattern and yellow halo.• Can spread rapidly with warm, humid weather

and defoliate plants.• Over-winters in crop debris, wooden stakes, and

in soil.

Organic management

• Cultivars vary somewhat in susceptibility.• Give plants more space; improved air

circulation.• Remove badly infected lower leaves.• Spray with fixed copper fungicide; other

organic sprays have not proven effective. Manzate (mancozeb) and Daconil 2787 (chlorothalonil) are chemical fungicides.

Septoria leaf spot… another foliar leaf spot disease

Cutting or pruning out suckers also increases air flow around leaves , reducing disease incidence.

Late blight – Phytopthora infestans

‘Iron Lady’ (resistant cultivar from Cornell breeding program) is available in 2013 from High Mowing Seeds.

Late blight fruit symptoms

Fusarium wilt of tomato

Fusarium wilt- brown streaking under stem epidermis; also visible in many cases on outside of stem.

Anthracnose- a fungal disease of ripe and overripe fruit. (Another reason to pick fruit at the “turning” stage).

ABIOTIC PROBLEMS

Frost/cold injury- leaf whitening, small gray/brown spots, or blotches

Phosphorous deficiency early in season due to cool soil and small root system

Edema- excessive soil moisture early in season, especially in containers.

Blossom drop due to environmental stress (usually high temp.). Photo courtesy: Jerry Brust, Ph.D.

Clopyralid herbicide injury

2,4-D herbicide injury

Blossom-end rot (nutritional disorder)

Epsom salt is NOT the answer.

Muskmelon leaf burned with pyrethrum and soap insecticide

“Catfacing”

Adventitious (aerial) roots

Physiological leaf roll (heat stress)

Concentric cracking

Radial cracking

Graywall (blotchy ripening); inside fruit walls are brown or black

Pithiness- excessive white tissue

Green shoulder

Uneven ripening

Zippering

Garden located next to large driveway that was resurfaced. Injury from petroleum products coming off “liquid asphalt cement”

Weird stuff…

ENJOY!

Resources

• Grow It! Eat It!http://www.extension.umd.edu/growit

– We have all types of practical food gardening tips and information. Check out our popular blog!

• Home and Garden Information Centerhttp://www.extension.umd.edu/hgic

– Here you will find factsheets, photos, and videos. You can also subscribe to the free monthly e-newsletter.

– We answer gardening questions 24/7…just click “Ask Maryland’s Garden Experts”

• Maryland Master Gardener Programhttp://www.extension.umd.edu/mg

– Consider becoming a trained MG volunteer!

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Howard CountyUniversity of Maryland Extension