Tips on deal­ing with trou­bled tomato plants

The Morning Call - - LIFE - Sue Kit­tek Sue Kit­tek is a free­lance gar­den colum­nist, writer, and lec­turer. Send ques­tions to Gar­den Keeper at [email protected] or mail: Gar­den Keeper, The Morn­ing Call, PO Box 1260, Allentown, PA 18105.

Over the last sev­eral years my tomato plants ap­pear to die off from the ground up. The leaves turn brown, new toma­toes stop form­ing, and the re­main­ing green toma­toes slowly ripen, but grow no big­ger. I was told I have a virus that kills off the plants, and the only cure is to not plant any toma­toes for four years. I used sep­a­rate pots this year, away from the gar­den, and used new bagged soil — yet the same thing hap­pened to the pot­ted plants. Do you know what is hap­pen­ing and if I can cure this sit­u­a­tion? Thank you.

— Bob in Beth­le­hem

Bob has made a good ef­fort to con­trol his prob­lem.

By us­ing clean pots and fresh soil, he has elim­i­nated one of the most com­mon prob­lems — in­fec­tion from soil-borne dis­eases. While it doesn’t elim­i­nate them, it does limit the sources of in­fec­tion. The cul­prits in­clude:

Bac­te­rial wilt: It sur­vives in the soil for years and en­ters the roots through wounds from trans­plant, cul­ti­va­tion or other in­jury. The dis­ease is most of­ten seen dur­ing pe­ri­ods of high tem­per­a­tures and high mois­ture. The fo­liage rapidly wilts but re­mains green and cut stems will look brown and ex­ude small amounts of yel­low ooze. Re­duce chances of in­fec­tion by: crop ro­ta­tion, three to four years with non­sus­cep­ti­ble plants (not pep­pers, egg­plants, pota­toes, sun­flow­ers, cos­mos, for ex­am­ple); and re­move and de­stroy in­fected plants (don’t com­post). Early Blight: The prob­lem win­ters over in the soil, on seeds and other host plants. It thrives in high hu­mid­ity and tem­per­a­tures. Small brown le­sions first ap­pear on older fo­liage and usu­ally near the bot­tom of the plant. They en­large, form con­cen­tric rings (bull’s-eye). The fo­liage quickly dies and there may be le­sions on the stem and fruit. Plant re­sis­tant va­ri­eties, ro­tate crops, con­trol weeds, mulch and space plants well apart. Trim and dis­pose of any in­fected leaves as they ap­pear.

Late Blight: This one thrives in cool, wet weather. The spots are small, dark and may ap­pear wa­ter-soaked. They en­large and show white mold on the mar­gins. Com­plete leaf loss may oc­cur in as lit­tle as 14 days. The fruits ex­hibit shiny dark le­sions. Pre­ven­tion tech­niques in­clude keep­ing the fo­liage dry (avoid over­head wa­ter­ing); al­low ex­tra space be­tween plants, de­stroy any vol­un­teer tomato, potato or other night­shade plants in the area; do not com­post rot­ten pota­toes and plant re­sis­tant cul­ti­vars.

Th­ese seem un­likely to be Bob’s cul­prit but there are plenty of other po­ten­tial vil­lains:

Sep­to­ria leaf spot: This prob­lem af­fects the leaves and stems but does not di­rectly at­tack the fruit. It thrives in cooler tem­per­a­tures (mid-60s to 70s). Start­ing on the lower leaves, it usu­ally oc­curs just as the fruit starts to set. Spots ap­pear — beige cen­ters with darker bor­ders on the older leaves. Sep­to­ria leaf spot weak­ens the plant and re­duces the size and num­ber of fruits. While not a soil-born dis­ease, the prob­lem will win­ter over in plant de­bris, de­cay­ing veg­e­ta­tion and wild host plants.

Bac­te­rial spot: This prob­lem at­tacks green toma­toes and is most prom­i­nent in wet sea­sons. Spots ap­pear on both the leaves and fruit. The spots are ir­reg­u­lar, some­times an­gu­lar and small. They ap­pear wa­ter-soaked on the leaves. Some­times the area around the spots will yel­low. The spot cen­ters dry out and tear. On the fruit, the spots are raised, some­times scabby. Bac­te­rial spot will re­duce crop yield, de­fo­li­ate plants and ex­pose fruits to sun­scald (be­cause of leaf loss). It is most com­mon dur­ing pe­ri­ods of wet weather and spreads eas­ily dur­ing heavy rain­storms. Wa­ter splash­ing, han­dling of in­fected plants (par­tic­u­larly while wet) also spread the prob­lem. While the leaves are af­fected by con­tact with the pathogen, the fruits are in­fected through in­sect bites or other wounds to the skin sur­face. Pro­tect your plants by ro­tat­ing crops; avoid­ing over­head ir­ri­ga­tion; clear­ing up all plant de­bris; re­mov­ing and de­stroy­ing any vol­un­teer plants, prun­ing to im­prove air cir­cu­la­tion.

In gen­eral

■ Clear up any plant de­bris as it oc­curs and re­move spent plants at the end of the sea­son.

■ Re­move leaves that be­come in­fected and dis­card.

■ Keep weeds un­der con­trol, es­pe­cially those that har­bor the prob­lem — any mem­ber of the night­shade fam­ily (datura, Jim­son weed, ground cher­ries, for ex­am­ple).

■ Never com­post dis­eased or in­fested plants.

■ Widely space plants, stake or cage them and con­sider prun­ing to im­prove air cir­cu­la­tion around each plant.

■ Wa­ter the ground, not the leaves and wa­ter early enough in the day to be sure that any wet fo­liage dries be­fore evening.

■ Ro­tate crops or, if us­ing con­tain­ers, use fresh soil and pots to avoid any soil­borne prob­lems.

■ Con­sider us­ing a food-ap­proved fungi­cide be­fore prob­lems ap­pear and reg­u­larly through­out the sea­son,

■ Se­lect cul­ti­vars that have re­sis­tance to dis­ease and fun­gal prob­lems.

■ Mulch to de­crease prob­lems with spores splash­ing up on plants.

■ Do not tend wet plants.

■ Clean and dis­in­fect tools be­fore mov­ing on to another plant. A sim­ple dis­in­fect­ing wipe works fine.

Note that while plant ro­ta­tion and/or fresh con­tainer soil are both good pre­ven­ta­tive mea­sures. The spores or bac­te­ria caus­ing the prob­lems can be trans­ported in by weather, weeds, an­i­mals or un­san­i­tary con­di­tions. So, other mea­sures are of­ten needed as well.

My tomato project this year has been a dis­as­ter. I started with five plants. One died be­fore I even planted it. Three were put into large pots and were eaten by cater­pil­lars. The re­main­ing one, a cherry tomato, sur­vived in a small hang­ing pot, but had it’s first flush of toma­toes eaten just as they ripened. I moved the plant out of range (at least from the deer, ground­hogs and rab­bits) and man­aged to har­vest two hand­fuls so far. They were tasty but hardly worth the ef­fort.

Thank good­ness our neigh­bor Jack plants his toma­toes in a fenced area and tends them faith­fully. He gen­er­ously shares his bounty, so sup­ple­mented by pur­chases from lo­cal veg­etable stands, we still en­joy fresh, lo­cal toma­toes. Jack has of­fered to grow a few of the heir­loom va­ri­eties I fa­vor in with his usual crop next year. I will prob­a­bly take ad­van­tage of his kind ges­ture — I watched an eight-point buck munch­ing what’s left of my hosta bed this af­ter­noon.

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