- Herbicide Plant Damage: How To Treat Plants Accidentally Sprayed With Herbicide
- Accidental Herbicide Injury
- Symptoms of Herbicide Injuries
- How to Treat Plants Accidentally Sprayed with Herbicide
- Roundup and roses don’t mix | The Sacramento Bee
- Rose rosette disease
- OOPS! I sprayed my lawn with Roundup. Now what?
- Tomato Herbicide Damage
- Wind damage
- Herbicide drift
- Herbicide residue
- Broad mite damage
- Tomato viruses
- Tomato leaf distortion: Unintended herbicide drift
Herbicide Plant Damage: How To Treat Plants Accidentally Sprayed With Herbicide
Herbicide plant damage can arise in a variety of forms. It is usually the result of unintentional contact with chemicals from spray drift or contact with vapor. Recognizing accidental herbicide injury may be difficult as the symptoms can mimic other plant conditions. Know the classic signs and learn how to treat plants accidentally sprayed with herbicide.
Accidental Herbicide Injury
The type of injury can be determined by the time symptoms begin to show. Problems that appear right after new plants begin to germinate are often the result of carry-over from previous applications, high rates of application, shallow planting and even poor timing.
Herbicide plant damage that appears on mature plants may be due to drift, misapplication, high temperatures or humidity, incorrect treatment and tank contamination. The home gardener will usually notice accidental herbicide injury on mature plants due to misapplication and timing.
Symptoms of Herbicide Injuries
The signs of injury will depend on the type of herbicide which contacted the plant. Post-emergence broadleaf herbicides are responsible for most injuries. These result in twisted leaves, cupped foliage, narrower new leaves, and roots that appear on the surface in annual plants. On ornamental grasses, these products cause yellowing and die back.
Pre-emergence controls are not as dangerous and herbicides that are applied systemically rarely result in problems unless they are over-applied. The exceptions are herbicides that have amine salt, which allows the chemical to liquefy and travel more easily through soil.
Non-selective herbicides will cause accidental herbicide injury in many instances and these controls must be applied according to directions and with caution. Symptoms of herbicide injuries from these products include yellowing in leaves, die back and general ill health in plants that might have been exposed. In some cases, fixing herbicide spray drift is possible if it is caught early enough.
How to Treat Plants Accidentally Sprayed with Herbicide
Contact non-selective herbicide injury is usually most evident in the leaves. A foliar method is used for application, which increases chances of drift. Plants accidentally exposed should have affected leaves pruned off to prevent the spread of the herbicide deep into the plant. It may also help to water the plant thoroughly to dilute the chemicals. If left untreated, the plant will eventually die.
Plants exposed to other chemical formulas may survive if you give them superior care for the next year. Keep the plant watered properly, fertilize in spring and prevent competition from weeds. If no other factors, such as disease or insects, are affecting your plant, then your leafy friend may outlive you.
Roundup and roses don’t mix | The Sacramento Bee
Garden Detective: What’s wrong with this rose? Exposure to the herbicide Roundup caused deformed and stunted growth. Debbie Arrington Sacramento Bee
Experts tackle readers’ garden questions.
“What’s wrong with my roses?”
Master consulting rosarian Baldo Villegas, who grows thousands of bushes at his Orangevale home, has heard that plea for help over and over this spring.
The major problem is not weather or pest related. It’s exposure to one specific herbicide: Roundup.
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“It’s the most common of all problems I get,” Villegas said. “I get photos or phone calls on almost a daily basis. It may look like something else, but it’s Roundup phytotoxicity.”
Phytotoxicity is the toxic effect on a plant due to such compounds as pesticides, herbicides, metals and salts. Roundup is one of America’s most widely used weed killers. Its active ingredient is glyphosate, which can kill most plants including roses. But it’s not just Roundup; glyphosate is found in more than 750 garden products.
“Roses are extremely sensitive to Roundup,” Villegas explained. “It can effect them for years (after exposure).”
A sure sign of this phytotoxocity is deformed growth on new foliage and stunted weirdly shaped flower buds. New leaves tend to be tiny and yellowed. Such exposure can be fatal to older bushes or bushes weakened by stress such as drought.
There’s no quick cure. With tender loving care and patience, the rose bush may eventually regain its health. But often, it remains compromised.
Roundup is so effective on weeds because of how it works. Sprayed on green leaves and stems, it penetrates a plant’s system and moves to roots and shoots where it prevents the plant from making certain proteins necessary for growth. It eventually kills the whole plant.
Most rose cases come from accidental Roundup exposure, Villegas noted. Drift of the herbicide spray settles on the bush’s leaves. Rose bushes several feet away may be effected.
Or a bush may be exposed via its roots after an application of granular herbicides (such as in weed-and-feed lawn treatments). Glyphosate binds closely to soil particles and can persist in the soil for six months, according to university research.
“We used to recommend using a sponge or paint brush to apply Roundup directly to weed leaves to avoid exposing other plants,” said Villegas, a retired state entomologist. “But I’ve found in my own garden, that doesn’t work. The (rose) bushes above those weeds are effected.”
The best solution: Avoid using Roundup in gardens with roses, Villegas said. “If you must spray, wrap your roses in plastic to protect them as mush as possible, then apply the herbicide only on cool and calm days with no breeze very early in the morning.”
The Bee’s Debbie Arrington is a consulting rosarian and lifelong gardener.
Questions are answered by master gardeners at the UC Cooperative Extension services in Sacramento and Placer counties. Send questions to Garden Detective, P.O. Box 15779, Sacramento, CA 95852. Send email to h&[email protected] Please put “Garden Detective” in the subject field and include your postal address. To contact UC Extension directly, call:
Rose rosette disease
Thank you for emailing the images. I’ve attached 3 here, and will soon add another 2. (I’m omitting 2 images because they are essentially the same as the CAM00331.jpg.)
It’s difficult to determine what is occurring with the roses. One thing for sure, we can rule out herbicide damage from glyphosate. But I’m uncertain we can call this rose rosette. The appearance as described by Clemson University (http://www.clemson.edu/extension/hgic/pest,s/plant_pests/flowers/hgic2109.html) is this:
- Shoots and foliage have an abnormal red color
- Stems appear thick and succulent
- Rapidly elongating shoots
- Shoots with shortened internodes
- Stems with an overabundance of pliable thorns
- New growth may have many branches that create a witch’s broom (similar to glyphosate injury)
- Distorted or dwarfed leaves (similar to 2.4-D injury)
- Deformed buds and flowers
- Abnormal flower color
- Lack of winter hardiness
- Spiral cane growth
Too many of the above signs & symptoms are missing from the images you sent. The only image which displays any “excessive thorniness” is CAM00332.jpg and there’s no way to determine, long-distance, if they are pliable as is typical with rose rosette.
The lab tests should resolve our questions.
If the tests are negative for the virus, I would investigate the cultural management. I suggest beginning with a soil test because some of the fertilizer “recipes” home gardeners use can cause soil imbalances of various fertilizer elements critical to a plant’s well-being.
OOPS! I sprayed my lawn with Roundup. Now what?
What is Roundup and how does it kill your plants?
During a recent landscape inspection, it quickly became apparent what was wrong with this lawn: Herbicide damage. We know that weeds can be extremely frustrating; especially when we’re getting a lot of rain and they seem to be taking over your landscape! While we promote the use of organic and natural methods to boost the health of your lawn, we know that sometimes you may resort to a chemical herbicide. Persistent weeds in hardscape features like sidewalks and driveways can be a challenge to control. However, if you do resort to an herbicide like Roundup, you should know exactly how it works and what it kills before you start applying it; or you may end up killing a lot more than weeds.
The homeowner applied Roundup to kill weeds in the lawn, but didn’t realize it would also kill surrounding turfgrass.
What is Roundup?
Roundup is what we call a “non-selective herbicide”. That means it can kills any plant it comes in contact with, including all lawn grasses, perennials, annuals, shrubs, vines, etc. Roundup’s active ingredient is Glyphosate, which you may now find in many other brands of herbicides. Glyphosate inhibits plant enzymes that are used to create amino acids. Without these amino acids, the treated plant will die. It is absorbed through the leaves and minimally through roots.
When you use a non-selective herbicide like Glyphosate, you have to be very careful that you only apply it to the plant you intend to kill. Even a few unintended drops on a neighboring plant or surrounding lawn will cause damage and even death. You should never apply herbicides when it’s windy, or you may end up with a lot of collateral damage.
Many homeowners and uneducated lawn care companies often spray herbicides like Roundup into their lawn to kill late winter and early spring weeds. They wrongly assume that because the warm-season lawn grass is dormant that the herbicide won’t hurt it. Unfortunately, turfgrasses like Bermuda, Zoysia and St. Augustine don’t typically go completely dormant in the winter. That means they can still be damaged by herbicides in the “off season”. You won’t realize how much damage is done until the remaining lawn (what’s left of it) starts to emerge in spring.
OOPS! I sprayed my lawn with Roundup. Now what?
If you unknowingly damaged your lawn with an herbicide like Roundup, you’ll have to do some physical renovation to the lawn. You’ll want to go ahead and remove the dead areas of lawn before more weeds move in to take its place. Then re-sod the patches or re-seed the areas, depending on the type of grass in your lawn.
As we always say, a healthy, vigorous lawn growing in healthy soil will naturally suppress a majority of weeds without the need for chemical herbicides like Roundup. Because chemical fertilizers and pesticides can damage soil life and wildlife, we always prefer to avoid them.
If you are currently on an organic lawn care regimen or on our Soil Building plan, know that you’ll probably need to remove some weeds by hand. The best results for a naturally gorgeous lawn come from a long-term commitment and a bit of patience.
Questions about your organic lawn and garden? Chat us up on Facebook and Twitter.
Tomato Herbicide Damage
Living on the water is not as glorified as you hear, constant maintenance, repairs and updates not to mention Northeastern Hurricanes. But its all worth it until Sandy came along. My story is mainly to tell you to be cautious of storm damage repair Companies and architectural Companies that you could be scammed with. We have been on the water for the last 30 years and never evacuated the property. So when Sandy hit to us is was just another board up lower floors, plenty of gas for the generator, food, water etc. This Storm was different. We were not prepared for the immense power and flooding this storm had and damage we received. Our deck off the house is on the beach and you step right on to the sand off it, after Sandy we had a 20 foot drop. The waves were close to 18-20 foot at times and that’s very rare for Long Island Sound. When it was over had 10 foot of debris piled up the length of the 70 foot driveway and we had 4+ foot of water in the first floor, all of our boarding was gone, we found our generator across the street in the marsh along with decking, parts of the house with others. Several of our vehicles were complete under water during the storm. Our Flood Insurance inspectors took a few weeks to get here and by then black mould had started growing through out the first floor so I decided to demo the lower level and had to separate our personal items for Insurance purposes and everything else went into the 40 yd dumpster. Our insurance Company arrived then processed our claim and now it was time to rebuild. We completely gutted the first level and had to have Environmental Companie come in to kill the mould and mildew. Once they were finished and certified the work I proceeded to rebuild. Since the South Shore on Long Island was hit so hard trying to fine a contracting Company to do the repairs was non existent. I decided to GC the work since I own a Property Maintenance Co. We finally finished. The next month FEMA came by to notify me, we now have to lift the house 14+ feet. It seems they decided to change the flood zone since Sandy and now we are in the (VE) zone, but the good news is we are eligible for the N.Y. Rising assistance Program for Hurricane damage repair. OK, We now have to hire a Architect.. We contacted 10 or so local architects which 7 of them told us they were to busy on the South Shore to take on new clients, which left 3 for us to interview. The first one had no experience with NY RIsing requirements, the second did not want to deal with NY RIsing at all and the third South Shore Architectural DPC claimed to be experienced with all NY Rising requirements and has many clients on the South Shore they are working with at present. WOW, sounded great finally this Horror story comes to a end, so I thought. They wanted 10% of the Awards for their payment as I receive the monies. $2500.00 up front for initial drawings, process, submit and get approved the 6100 and all Town permit and NY Rising requirements as needed. This is stage one. Stage 2 is a $7500.00 down which consisted of 3 different drawings for rebuilding as per the 6100 approvals, several meeting’s to fine tune the drawings which never happened, we had to cancel one my wife’s Cancer treatment.. At this point my NY RIsing Rep, contacted me that the 6100 was questionable from the construction dept and there were several issues that South Shore Architectural (SSA) has not addressed or addressed improperly. SSA claimed all was proper and they (NY RISING) does not know what they are talking about. Now I am in the middle of a war between Peter Scavone of SSA and NY Rising. The turn out is that SSA South Shore Architectural DPC Peter Scavone and Dmytro Chornobryvets have no clue what they are doing in the NY Rising Program in fact up until the last week of dealing with Peter I thought Peter Scavone was the Architect and have never met Dmytro Chornobryvets, the real Architect. Be very careful on choosing a Architectural Company because you could end up like us going through a horror of loosing almost everything in a hurricane and then have a fast talking con man like SSA’s Peter Scavone take you down the road of more horrors. To clarify, my NY Rising Rep and those of NY Rising construction kept telling me your Architect is not complying to our attempts to have them send in the modified 6100 and drawings that we need to approve, we also need to have the DEC Wet Land permit applications submitted. When I questioned Peter Scavone on this he just kept saying "we owe them nothing" and "they do not know what they are talking about". He stated, he has a high up connection in NY Rising that is handling it for him, and we do not need DEC WET Land Permits. I finally found out who his high up connection is and he told me that Peter Scavone has completely disregarded what he explained to him. DEC Wet Land Permits ARE required. he hardly knows Peter Scavone or SSA.. So once again this Carney Hustler SSA Peter Scavone tried to pull another fast scam on procedures he has no idea of the correct NY Rising Procedures, our Awards Letter was in complete jeopardy of being cancelled. Since the horror of the last several years with SSA and finally firing him and of course him not returning any my NY Rising monies of $10,000.00. I am proceeding to file charges and in the process of contacting several other SSA customers who are in the same position as us being scammed by South Shore Architectural and Peter Scavone.
By: Joe Masabni, Juan Anciso, and Russ Wallace
If the leaves on your vegetable plants are twisted or curled, the problem could be environmental, chemical, or biological. Sometimes all the leaves on a plant are twisted or curled; sometimes only new growth has symptoms while older leaves are normal. Damage may start moderately then quickly begin to affect new growth. Damage to tomato and other vegetable plants may have one or a combination of causes (Figs. 1-5).
There are five primary reasons that tomato leaves twist or curl:
- Wind damage
- Herbicide drift
- Herbicide residue
- Broad mite
- Tomato viruses
High winds, blowing dust and low humidity can damage the leaves and stems on tomato plants. Injury is similar and is often confused with drift damage from phenoxy-type herbicides (Fig. 6). Heat and low moisture can cause the edges of the tomato leaves to die back, then twist and curl.
Hot dry weather may also cause a symptom called physiological leaf roll. This is a self defense response, where leaves and leaflets curl slightly to prevent further water loss (Fig. 7). Mild leaf roll generally does not lower yields or quality, though severe symptoms may cause flowers to drop and fewer fruit to set.
These symptoms may look like damage from other causes, but if wind damage is the only problem, plant health will generally normalize once weather conditions improve.
Crops and pastures are often treated with herbicides to prevent or eliminate weeds, and drifting spray can damage tomato plants. Up to 84 percent of the cotton acreage in Texas is sprayed with broad-spectrum herbicides. They are also used on cereal and grain crops. The problem is that wind speeds as low as 5 mph can move these herbicides up to a mile.
Many home gardens are close enough to cotton and corn fields for drifting 2,4-D, dicamba, or other hormone-type herbicides to cause serious damage. Tomato plants are extremely sensitive to these herbicides: they can be injured by concentrations as low as 0.1 ppm. If only a little of the herbicide reaches the tomato plants, they can recover, but yield will definitely suffer (Fig. 8).
In addition to commercial applications, herbicides from home gardeners or their neighbors can drift onto sensitive tomatoes or other vegetables. Weed killers for lawns and landscapes often contain broad-spectrum herbicides such as glyphosate and the growth regulators such as 2,4-D and dicamba. Examples are Ortho Weed-B-Gon and Fertilome Weed FreeZone. Tomatoes are very sensitive to these herbicides even when applied at extremely low rates. Though the plants may look healthy, drift from these products can reduce the number and the quality of the fruit.
There is no remedy for leaves that are already injured by 2,4-D. If new growth continues to show injury symptoms, harvest any salvageable fruits and pull up the plants.
If new shoot growth is normal, and there is still at least 4 to 6 weeks left in the growing season, the plants may be able to outgrow the injury. New buds and leaves should begin growing within about a week. If not, pull the affected plants and replant.
To minimize herbicide drift following these steps:
- always read and follow the herbicide label instructions
- avoid spraying when wind speed is more than 5 mph
- avoid spraying when wind is blowing toward sensitive crops
- use a hooded sprayer when applying postemergence herbicides near growing plants
- reduce spray pressure so droplet size is larger and less likely to move with the winds
- reduce the speed of the spray application to avoid movement in the circulating air
- ensure that the dosage applied is correct
- use the correct spray nozzles/tips for the chemical to be applied
- use drift reducing spray additives if available
- wash out all previous herbicide from inside the spray tank
Vegetables can be damaged by herbicides left in mulch or compost made with hay or manure from fields that have been sprayed with Grazon, GrazonNext, or GrazonNext HL. The active ingredient in these products is aminopyralid which persists for 18 months on treated hay and hay products. It also persists in the manure of animals that eat Grazon-treated hay. Grazon products are commonly used in pastures because they kill about 100 difficult broadleaf weeds .
The GrazonNext label states that any plant matter collected from fields sprayed with aminopyralid may not be used in compost or where vegetables are to be grown (Fig. 9). The label also states that the “applicator must provide the land manager with a copy of instructions regarding uses of forage from areas treated with aminopyralid.”
Anyone who sells hay, silage, haylage, green chop, or bedding material that was treated with aminopyralid, is responsible for alerting the buyer that it was treated and must not to be used in composting or were vegetables are grown. Buyers must also ask whether aminopyralid was used on the source forage within the last 18 months.
Additional restrictions in hay and manure use:
- Do not use aminopyralid-treated plant residues, including hay or straw from areas treated within the preceding 18 months, in compost, mulch or mushroom spawn.
- In compost, mulch, or mushroom spawn, do not use manure from animals that have eaten forage or hay from treated areas within the previous 3 days.
- Do not plant broadleaf crops (including soybeans, sunflower, tobacco, vegetables, field beans, peanuts, and potatoes) in fields treated in the previous year with manure from animals that have grazed forage or eaten hay harvested from aminopyralid-treated areas until an adequately sensitive field bioassay is conducted to determine that the amount of aminopyralid residues in the soil will not injure the crop to be planted.
- To promote herbicide decomposition, burn the plant residues or evenly incorporate them in the soil. Aminopyralid breaks down faster in the plant residues and manure when the soil is warm and moist. Irrigation can speed up the process.
Broad mite damage
Broad mites (Polyphagotarsonemus latus) affect many plant families, including tomato, pepper, eggplant, potato, cotton, and citrus. It also attacks ornamentals such as dahlia, zinnia, chrysanthemum, pittosporum, and schefflera that are grown under shade cloth. Broad mites avoid light and feed on young leaves and flowers. As they feed, they inject toxins that severely twist and distort the leaves. The damage may resemble other types of damage on tomato plants. In Texas, broad mites damage seedlings grown in greenhouses or under shade cloth. Severe broad mite infestations can make the underside of leaves and fruit look bronzed or russetted.
These mites are invisible to the human eye and can be overlooked even under a magnifying glass. They are usually discovered only after plant injury is noticeable. Broad mites are 0.10 to 0.30 millimeters long (Fig. 10), have oval bodies, and can be translucent to pale brown or yellow.
If you cannot see the broad mites readily, look for the eggs, which are white, oval-shaped and have ridges or bumps. This mite’s eggs are distinct—they look like Christmas ornaments (Fig. 10). Eggs develop into adults in about 4 to 6 days in hot weather and 7 to 10 days in cool weather.
Broad mite populations come and go rapidly depending on food, weather, and light. Infestations are often sporadic and fluctuate from year to year. Broad mites may infest your tomato plants via transplants from greenhouses or the legs and antennae of whiteflies.
Before treating the plants, make sure that broad mites are the problem. Entomologists with the Texas A&M AgriLife Extension Service can diagnose leaf samples for you (http://plantclinic. tamu.edu). If broad mite damage is severe, pull up the plants and dispose of them.
Moderately affected plants can be treated with sulfur-based miticides. However, be sure that the tomato cultivar is tolerant of sulfur before applying it. Do not treat tomatoes when temperatures are higher than 90°F or when the plants are water stressed—the miticide can damage the plant under these conditions. The plants will likely need additional applications to avoid further damage. Other products known to control mites in general include Horticultural Oils and Insecticidal Soaps. You can alternate these treatments with predatory mites that attack and consume broad mites. Predatory mites are most effective if used before the broad mites get firmly established. Predatory mites are sold by many companies specializing in organic products (Grow Organic, Arbico Organic, Benemites are a few examples)
Hundreds of viruses can cause leaf curling and stunting in tomatoes. Though initial virus symptoms can be confused with a phenoxy-based herbicide damage, the disease often progresses to include yellow-green mosaic patterns on the leaves (Fig 11).
Viruses in the geminivirus group are most often the culprit for virus-based leaf twisting in tomatoes. In Texas, the most common virus encountered is the tomato yellow leaf curl virus.
Geminiviruses spread to tomatoes and other plants exclusively by the sweet potato or silverleaf whitefly (Bemisia tabaci). To reduce the spread of this virus, manage whitefly populations with insecticidal oils and soaps.
This group also includes other viruses:
- the tomato yellow leaf curl virus
- chino del tomato virus
- tomato leaf crumple virus
- pepper huasteco virus
- potato yellow mosaic virus
- Sinaloa tomato leaf curl virus
- Texas pepper virus
- tomato yellow mosaic virus
- tomato yellow streak virus
New tomato varieties have been developed that resist tomato yellow leaf curl. However, these varieties are still susceptible to other virus diseases. As with any tomato leaf damage, you must identify the cause before making any management decisions. To confirm tomato yellow leaf curl virus, submit plant samples to the Texas Plant Disease Diagnostic Laboratory (http://plantclinic.tamu.edu). Pull up and dispose of diseased plants.
They key to solving the problem of twisted or curled leaves is to identify the source or sources of the problem. Wind damage will resolve once conditions improve. Mites and viruses can be identified by laboratory analysis. Damage caused by herbicide drift or residue in mulch and compost is the most difficult to identify. Regardless of the cause, curled or twisted leaves on tomatoes or other vegetables are a sign that you may need to take action to save your crop.
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Tomato leaf distortion: Unintended herbicide drift
Drift from herbicide applications can lead to unintended side effects in greenhouse crops. Symptoms of distorted growth on tomato plants are discussed here.
by Josh Henry (graduate student in floriculture) and Brian E. Whipker (Professor of Floriculture at North Carolina State University)
There are a number of risks to applying herbicides in the greenhouse. In addition, herbicide drift and volatilization can cause severe damage to nearby crops (e-GRO Alert 4-14). Symptoms can vary depending on the herbicide and the species in question, but leaf distortion and epinasty are both common plant responses to synthetic auxin herbicides, such as 2,4-D and dicamba (Israel et. al, 2013).
Figure 1. Many plants exhibited a severe distortion of the new growth. (photo: Josh Henry)
An issue for growers is that herbicides may drift from adjacent fields or neighbors’ yards and enter the greenhouse. In this case, even the most careful grower may encounter symptoms of herbicide damage on their crops. This situation was encountered on a recent grower visit. Severe symptoms of distortion were observed on a crop of 1 gallon ‘Better Boy’ tomatoes. The grower had not applied any herbicides recently, so herbicide damage was not initially considered as a possibility.
Figure 2. Symptomatic plants were twisted and distorted at the apical meristem. (photo: Josh Henry)
The affected plants were located on a single bench nearest the outside wall of the greenhouse. Symptom severity varied from plant to plant, but many plants exhibited at least some symptoms. The most common symptom involved a thickened and distorted appearance to the newest growth (Fig. 1). The apical meristem was also had this appearance, with some twisting of the upper stem (Fig. 2). Symptoms were not as severe on some plants, but the twisting and distortion was still present (Fig. 3). A comparison of healthy to symptomatic leaves may be seen in Fig. 4.
Figure 3. Some plants were less symptomatic, but exhibited twisting and distortion of the new growth nonetheless. (photo: Josh Henry)
A variety of other common greenhouse problems can lead to distortion similar to what was observed in this crop of tomatoes. For instance, broad mites, boron deficiency, or gas leakage from a cracked heat exchanger could all lead to similar symptomology.
Figure 4. A range of symptoms can be seen here compared to a healthy tomato leaf on the left. (photo: Josh Henry)
Broad mites are very small and can be difficult to detect without a microscope or powerful hand lens. Upon observation of the affected plants, no signs of these pests were present. With symptoms this severe, there would have been an abundance of broad mite eggs easily seen with the proper magnification. This indicated that the issue was not caused by broad mites are similar arthropod pests.
Although the new growth was distorted, the symptoms were not the same as boron deficiency. One major difference here was that the apical bud was still healthy and growing. With a boron deficiency, death of the apical meristem would have occurred, leading to a plethora of side shoots emerging. These symptoms were not observed either, indicating that it likely was not nutritional. In addition, all the plants of this cultivar were affected. Widespread damage is not typical for a boron deficiency problem and more probable with a physiological problem such as herbicide drift.
Lastly, there were no cracked heat exchangers present, or other obvious sources of ethylene gas. Tomatoes quickly respond to ethylene with curling and distortion of the leaves and stems, similar to what was observed here. Without any source of ethylene, this potential cause could also be ruled out. In addition, other plants which were transplanted later into the same greenhouse did not exhibit symptoms. One would expect ongoing problems with a heater issue.
Figure 5. After several weeks, the symptomatic plants began to recover with healthy, normal growth. (photo: Josh Henry)
With these other issues accounted for, it appeared most likely that the distortion on these tomatoes was the result of herbicide damage. Other details supporting this conclusion include the fact that the plants were located nearest to the outer wall of the greenhouse, and thus would have been the first affected by herbicide drift coming from the outside. Herbicides can easily volatilize and be carried for great distances, so it can be difficult to determine the source.
Figure 6. Although the new growth was healthy in appearance, the distorted growth remained present further down the plant. (photo: Josh Henry)
In this case, we took some of the most symptomatic plants back to our greenhouse for observation. After several weeks, these plants began to develop healthy new growth (Fig. 5). The symptomatic foliage retained its distorted appearance (Fig. 6); however, the new growth was quickly covering the symptoms, indicating that the plants may recover.
Take caution when applying herbicides in or around your crops, and be aware of the mode of action. Synthetic auxin herbicides such as 2,4-D and dicamba can volatilize especially easily and should not be applied near sensitive species such as tomatoes. The weather and wind conditions can also make a difference in how easily herbicides may volatilize or drift. For instance, hot and dry conditions favor the volatilization of herbicides, and high winds may carry droplets or vapor for long distances. Depending on the droplet size, herbicides have the potential to drift several hundred feet up to several miles (Dexter, 1995).
Make sure to keep in contact with neighboring farms and other agricultural operations, and request to know when synthetic auxins will be applied to surrounding areas. Knowing when these herbicides are being applied will enable you to take the actions necessary to prevent drift coming into the greenhouse.
These factors can pose challenges to growers, but emphasize the importance knowing the chemicals you are applying and the potential risks they may cause to your crop.
- Dexter, A.G. 1995. Herbicide spray drift. North Dakota State University Extension Service. NDSU Extension Service EXT A-657.
- Israel, T. D., G. N. Rhodes, and A. L. Wszelaki. 2013. Diagnosing Suspected Off-target Herbicide Damage in Tomatoes. University of Tennessee Extension. UT Extension Fact Sheet W 295-B.