By: Bonnie L. Grant, Certified Urban Agriculturist
Leaf roll is a well-documented symptom of several virusesand diseases. But what causes physiological leaf curl on tomatoes that are notdiseased? This physical anomaly has several causes, mostly cultural. Is tomatophysiological leaf roll dangerous? The curiosity has not been shown to reduceyields or plant health but seems to concern gardeners nonetheless. Read on fortips on preventing physiological leaf roll on tomatoes.
Curledtomato leaves can be caused by factors like disease, environmentalchanges, and even herbicide drift. In healthy plants, the causes ofphysiological leaf roll in tomato can be difficult to uncover. This is becausethe effect may be caused by one situation or the result of several, and naturehas a place in the occurrence. This can make uncovering the reason a bittricky.
Seemingly healthy tomato leaves will curl or roll at thecenter, producing a loose cigar-like effect. The lowest, oldest leaves are affectedinitially. At first glance, it seems to be a response to lack of water or heatand that first inkling may be based in fact. Or it could be something else.
The condition can occur at any time during the growingseason and does not affect the stems, flowers or fruit. It seems to occur morefrequently in indeterminatevarieties of tomato. Cultivars which produce high yields also seemto be more susceptible.
No information on physiological leaf roll on tomatoes listsit as an issue of concern. Since fruiting does not seem to be affected andplants remain relatively healthy, it simply produces unnecessary distress inthe gardener’s mind. The plant will continue to produce and grow until the endof the season.
In order to calm any fears, it is important to consider whatmight be contributing to the phenomena. Possible suspects include:
Selecting determinate cultivars may be key to preventingphysiological leaf roll on tomatoes. Keeping soil temperatures below 95 degreesFahrenheit (35 C.) by using mulch or evaporative cooling is also an effectivestrategy.
Avoid over fertilizing and excessive pruning. Maintainconsistent soil moisture and make sure young transplants are hardened offbefore planting outdoors. Be cautious when weeding around young plants to avoiddamaging the roots.
If you are spraying a chemical herbicide in the garden, doso when there is no wind to avoid unintended chemical injury.
Plants can recover if conditions become more favorable andyour tomato crop will be unaffected.
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Tomatoes (Solanum lycopersicum) are summer favorites of home growers for their rich flavor and ease of care. However, tomatoes are susceptible to environmental problems, diseases and physiological disorders that can result in distressed plants. One sign of a problem with tomatoes is leaf curl, which is associated with multiple pathogens. Identifying the cause is essential to finding the best solution for this potentially devastating problem.
When strong winds arrive, they can cause damage to plants in a number of ways. The wind itself can knock over tall tomato plants that are not staked and tied properly.Wind can cause rapid evaporation, which can lead tomato plants to curl up their leaves.
The wind can also blow dust and dirt around at high speeds. This fast-moving dust and dirt can damage the leaves of plants and cause them to curl in response.
Strong winds also cause leaves to lose water rapidly, due to accelerated evaporation. Again, a plant’s leaves will curl up in an attempt to slow down water loss due to evaporation.
As mentioned above, you can use cloches to cover your young tomato plants and protect them from strong winds. You can also use row covers, although these might not provide as much protection as cloches.Cut the bottom out of a plastic bottle and use the top as a cloche to protect young plants.
A more effective solution is to use a windbreak to protect your garden. Some examples include: