club root cabbage

7/27/2019 Club Root Cabbage

1/3

Clubroot of Cabbage

Clubroot is a very serious disease o cabbage andclosely related crops. Te most susceptible cropsinclude cabbage, Chinese cabbage, Brussels sproutsand some cultivars o turnip. Other related crops that

may also be attacked include kohlrabi, kale,caulifower, collards, broccoli, rutabaga, sea kale, allturnips, and radishes. Weeds in the mustard amilymay be inected and result in enhanced diseaseproblems on the susceptible crops.

Te symptoms rst noticed will be a decline o theplant including yellowing o leaves, and a tendencyto wilt during hot days. Examination o the roots willreveal swollen, club-shaped roots instead o thenormal ne network o roots (Fig. 1). In severe casesmost roots will be aected (Fig. 2). Te swollenroots will begin to decay and eventually disintegrate.

Symptoms and Signs

Plasmodiophora brassicae

Figure 2: Close-up of the club shaped roots.

Clubroot is caused by the ungus Plasmodiophorabrassicae. Te important eatures o its lie historyinclude its longevity in soil, means o spread, and itsreaction to soil pH. Ater the disease has occurred,the ungus can survive rom seven to ten yearswithout any susceptible plant ever being grown there.I any susceptible crops or weeds grow during thisperiod, the ungus may become more prevalent.

Introduction

Figure 1: Clubroot symptom on cabbage.

Slightly inected plants may show ew symptomsabove ground other than slow growth and will havevery small knots on roots. Young inected plants maynot show severe enough symptoms to be detected.

Disease Cycle


2/3

Management Strategies

Since the ungus survives in soil and in dead cropdebris, any movement o these may result in transero the ungus to a new site. Tereore, usually all o asmall garden will be aected once the disease hasbecome noticeable. Resting spores o the ungus areproduced in the swollen clubroots and released intothe soil when these disintegrate.

Tere are several approaches to managing clubroot,all o which may be used when appropriate. Te rstdeense should be aimed at excluding the disease.Avoid purchasing inected transplants. Buy only romreputable garden store or grower as inectedtransplants cannot always be identied. It is sae togrow your own transplants because the ungus is notcarried on the seed. I transplants are to be grown,

care must be taken to use clean or sterile soil mixesor the seed bed.

Do not move plants or soil rom one garden toanother garden. Tis invites trouble unless it can bepositively determined that no clubroot has occurredin a garden. Be sure to clean shoes and tools

thoroughly beore working in a garden. Controlweeds to avoid potential build-up o the disease onthem.

I inected plants have occurred in a garden, limingmay reduce or completely control the disease. TepH o the soil should be raised to 7.2 or higher with

hydrated lime. ABLE 1 on the ollowing pageshows how much to use or measured pH levels. SoilpH testing is available at some local CooperativeExtension oce and garden stores. Use at least 4pounds per 100 square eet (9.3 square meter) ohydrated lime i the pH is below 8. Te additionallime needed may be in the orm o limestone or airslaked lime, but these alone will not completelyeradicate the disease. Also liming will not be veryeective on light sandy or muck soils, but will giveexcellent control on heavier soils. Some other crops

will be injured i grown on soil with such a high pH.Adjustment may be necessary beore another crop isgrown. Do not grow cabbage or more that one yearin a row where heavy liming is required; theaccumulated lime will be dicult to counteract orother crops.

pH Amount of lime to apply:5.0 12 per 100 sq t 1250 per 1/4 acre

5.5 10 per 100 sq t 1000 per 1/4 acre

6.0 7 per 100 sq t 750 per 1/4 acre

6.5 5 per 100 sq t 500 per 1/4 acre

7.0 4 per 100 sq t 375 per 1/4 acre

7.5 4 per 100 sq t 375 per 1/4 acre

8.0 none none

TABLE 1:Amount of lime to apply for clubroot control.


3/3

Tis publication may contain pesticide recommendations. Changes in pesticide regulations occur constantly,some materials mentioned may no longer be available, and some uses may no longer be legal. All pesticides dis-tributed, sold, and/or applied in New York State must be registered with the New York State Department oEnvironmental Conservation (DEC). Questions concerning the legality and/or registration status or pesticideuse in New York State should be directed to the appropriate Cornell Cooperative Extension Specialist or yourregional DEC oce. READ HE LABEL BEFORE APPLYING ANY PESICIDE.

Te Plant Disease Diagnostic Clinic at Cornell University is located at 334 Plant Science Building, Ithaca,NY, 14853. Phone: 607-255-7850, Fax: 607-255-4471, Email: [email protected] or [email protected]

Tere are currently no home garden productsregistered in New York to help manage this disease.Although resistant cultivars o cabbage are not readilyavailable there is at least one, Badger Shipper, that hasa air amount o resistance. In some situations thiscultivar may solve the management problems.Resistant turnips, radish and rutabaga varieties are

also available.

References:Clubroot o Cruciers, .A. Zitter, Vegetable MDOnline. http://vegetablemdonline.ppath.cornell.edu/actsheets/Cruciers_Clubroot.htm.

Compendium o Brassica Diseases, APS Press.

Vegetable Diseases: A Colour Handbook, S.. Koike,P. Gladders, and A.O. Paulus. Academic Press.

Updated, SLJ, 12/12

club root cabbage

Documents