Sclerotium rolfsii
Southern blight is fear by home gardeners and commercial-grade growers alike .
TheSclerotium rolfsiifungus that causes the disease is believe to be able-bodied to lie dormant in the soil for up to four years .
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Mature sclerotia. Photo by Jason Brock, University of Georgia, Bugwood.org.
Once temperature and humidity conditions are ripe and it finds a host flora on which to become establish , it is extremely hard to eradicate .
Rather than endeavor to treat an infection , it ’s far considerably for vegetable gardeners to concentrate on preventing southerly blight in their tomato plants before it gets established .
In this guide , we ’ll partake tips for cultural control , as fungicides available to plate growers are largely ineffective against this pathogen .
Mature sclerotia. Photo by Jason Brock, University of Georgia, Bugwood.org.
Here ’s what to expect :
What You’ll Learn
Symptoms of Southern Blight in Tomatoes
Symptoms of infection are hard to lose in once healthy , green Lycopersicon esculentum flora . The leaf change by reversal a sickly yellow semblance and begin wilt very cursorily .
Unlike bacterial wilt orother common love apple ailments , this blight also causes a wound to form around the collar of the tomato radical , girdle it where it come in contact with the ground .
The lesion is usually cover in a white mold , called mycelium .
Within the darn of mycelium are round , beadlike fungous structures of a white-hot or cream color .
They turn brown at maturity date and attend a bit like Indian mustard cum , readily light to the ground to rest in the grime .
These beads are calledsclerotiaand they are small enough that many gardeners do not even notice them , unwittingly spread them around the garden via footwear or instrument .
The sclerotium can weather through several seasons , live through rough heat . Their master exposure is that they ca n’t survive extreme cold .
The reason the disease is called “ southern ” blight is because it is more dominant in the warm , humid condition of the southern US .
Sclerotia bond themselves to decaying plant issue on and in the ground before infecting intelligent plants . In add-on to make the plants to droop , within three or four days of contagion they can get the fruits to mature prematurely , ruin some or all of your crop .
Plants suffering from southern blight may also mould “ adventitious ascendent organization , ” small roots on the depleted stems that bet like yellow-bellied stubble .
In the absence of any other symptoms these ascendent are not a true index number that your plant are suffering from southern blight , as they may be because of other stressor .
tomato plant are not the only plant susceptible to infection . Southern blight can taint over 500 unlike plants .
Other pop backyard garden plants includingbeans , eggplant bush , peas , peppers , Citrullus vulgaris , andcarrotscan also play host to the fungus .
If the genus Sclerotium from these other infected vegetables remain in the soil where tomato plant are later planted , the fungus can taint the new seedlings .
Read on to acquire about other factors that encourage southerly blight .
Sources of Infection
Several fairly ordinary gardening conditions can lead to southern blight infection , or make it worse .
Seedlings purchased from any nursery that reuses pot soil or does not sterilize reused container are an often overlooked reservoir of initial infection .
Sclerotia multiply more quickly in humid condition combine with temperature between 77 and 95 ° F .
A long period of raging , dry weather followed by heavy rain will goad the fungus into action . Once it starts to open , a blight attack can destroy an intact crop in twenty-four hour period .
Sclerotia remain confined to one area of soil in a garden if they do n’t have a legion plant to live on .
But many gardeners industrial plant multiple varieties in different parts of the vegetable garden on the same day , digging in one part of the garden and then digging in a different part .
Failing to sanitize gardening tools between plantings is like to a surgeon manoeuver on a patient without cleaning their scalpel or hands first or afterwards .
This is the immediate way to spread southern blight and taint an entire garden .
Many gardeners also prefer togrow love apple in with child patio container .
While this is easier than digging in tough ground , the buildup of high temperature and wet in containers can make an ideal environment for the fungus to boom .
How to Prevent Southern Blight
Your betting odds of avoiding southern blight are greater when tomato are planted in the ground with wide spaces between plant to allow sufficient air circulation , rather than planting thickly or in container .
strain circulation helps to ensure the stems remain dry at the filth line where the fungus is know to assail .
It ’s also a good idea to keep plots weed to deprive the fungus of additional potential hosts and to reject debris where they could overwinter at season ’s end .
A ordinarily overlooked source of Sclerotium is the scandal catch in the tread ofgarden shoes .
Walking through infected soil and then tramping through the garden may permit southerly blight fungi to hitchhike a drive , and you may hold spore or sclerotium into other section of the railyard .
Some gardeners utilise crop rotation to help lessen the number of genus Sclerotium in the soil .
The idea is that over time when the sclerotia can not find a worthy boniface , they set about to die off . This is a plausible method that could practicably take two or three twelvemonth to come through .
Rotating with harvest that are fairly resistant to the disease such ascorn , wheat , sorghum , or oats can facilitate cut the sclerotia in the soil .
take away works debris and keep open a tidy garden can help forbid the sclerotia from getting a foothold .
A study conducted in 2022concluded that the use ofbeneficial fungi in theTrichodermagenus , could suppress the increase ofS. rolfsii .
dogma ® WP comprise two Trichoderma species , T. asperellumandT. gamsii .
It should be apply to the grime seven days before planting as a preventive measurement . Note that this merchandise will not treat an subsist contagion .
Tenet ® WP
you may find Tenet ® WPavailable at Arbico Organicsin 16 - ounce software program . Be trusted to interpret the directions carefully before covering .
Treatment Options
Unfortunately there is no discussion for a southern blight contagion . sealed chemical fungicides are available for commercial growers but these are not feasible for use in the home garden .
If you chance upon your tomato plant plant are infect , you ’ll need to dig them up and dispose of them in the methamphetamine – do n’t put them on the compost pile !
If you are growing your crop in container , dispose of the soil and be sure to sanitize the stack with a 10 percent bleach solution ( nine parts water supply to one part bleach ) before reuse .
you may solarize the soil in the infected garden bottom , by placing plastic sheeting over the surface of the stain for about eight weeks during the summer calendar month .
After solarization and prior to planting , you may treat the ground with Tenet WP , mentioned above .
A Pox on Tomato Southern Blight
levelheaded gardening practices and a keen eye for other indication are your best defense against southern blight in a homegrown love apple crop .
Should you belooking for selective information about other tomato diseases , these guides might be of habit :
© require the Experts , LLC . ALL RIGHTS RESERVED.See our TOSfor more item . Originally published on August 15 , 2014 . Last updated August 1 , 2023 . intersection pic via Arbico Organics . Uncredited photos : Shutterstock .
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Rose Kennedy
