Feeds:
Posts
Comments

Archive for the ‘Vegetable Gardening’ Category

Cyclamen mite damage on sweet peppers

We sure didn’t have much luck with our vegetable garden this year. The tomatoes produced half-heartedly, the summer squash succumbed to disease and vine borers before providing very many squash, and the corn was torn down and destroyed by some critter before the ears had completely filled out!

Rattlesnake pole beans - my favorite!

Rattlesnake pole beans – my favorite!

We did get quite a few cucumbers before disease claimed the vines and I was able to can 42 pints of pickles. The rattlesnake and purple pole beans have also done very well. We were, however, disappointed in the ‘Lazy Housewife’ pole beans that we tried this year. They were very slow to develop and when they did, the beans were tough and leathery. We are just letting them dry on the vines and will use them for dried beans.

Last weekend we harvested all our butternut squash. There weren’t as many as last year but I hope they are as good. The other winter squash we grew was Buttercup. This variety was new to us but it is absolutely delicious! The flesh is a beautiful bright orange and couldn’t be sweeter! This one is definitely a keeper – we will be planting it again next year.

Close up of the rough, scaly skin of one of the affected peppers

Close up of the rough, scaly skin of
one of the affected peppers

Our bell peppers provided some of the strangest looking fruits in the garden. From the top (at the stem end), they looked fairly normal but at the blossom end, the skin was light brown, rough, and hard. In many cases, the whole bottom half of the pepper was like this. I knew it wasn’t blossom end rot because the flesh wasn’t really damaged – it was quite superficial. I had never seen anything like it before.

I thought perhaps it was environmental or maybe a mosaic virus but nothing really fit. Then I wondered if it had something to do with the herbicide drift that injured our tomato plants back in the early summer but the descriptions of herbicide damage to peppers didn’t really match what was going on with our peppers.

Finally, after reviewing photos of pests and diseases of sweet peppers, I found the answer – cyclamen mites! I never would have thought that this was an insect problem. Well, actually, mites aren’t insects but you know what I mean.

Russeted skin covers the whole bottom half of this pepper.

Tough, russeted skin covers the
bottom half of this pepper.

Cyclamen mites (Phytonemus pallidus) are tiny mites that attack many different plants including peppers and tomatoes. As these little pests feed, they inject chemicals into the plant tissue. These chemicals act as growth regulators and cause abnormalities in the foliage and fruit.

Feeding in the foliage causes crinkling and twisting of the leaves and sometimes leads to the formation of larger than normal leaves. I wish I had taken a picture of the foliage because that was another thing I noticed about these pepper plants; their leaves were huge and puckered.

The damage is only skin deep!

The damage is only skin deep!

When cyclamen mites feed on the developing fruit, their salivary secretions cause the skin of the fruit to become tough and russeted. This tan, rough skin was very obvious and fairly extensive on many of our peppers. It mostly occurred at the blossom end and seemed to restrict the normal growth/expansion of the fruit – almost like the pepper was constricted by tight netting.

Though the russeting is superficial, it essentially ruins the part of the fruit that it covers. I did peel some of the tough skin off one of my peppers and tasted it to see if the flavor was affected. I thought it tasted a bit weird but that could have been all in my head. Still, I ended up tossing the majority of the defective portions in the compost.

Some of the peppers had less of the russeting over the skin.

Some of the peppers had less of
the russeting over the skin.

University of Maryland Extension says that cyclamen mites can be a “minor pest of pepper and tomato”. When we lost so many peppers this year, it didn’t seem like a minor problem to me!

I’m sure what they meant is that they aren’t common pests of peppers in the vegetable garden. Apparently, these pests are more common in greenhouse situations. We did purchase a few of our pepper plants from a greenhouse so perhaps we introduced them to the garden that way.

Despite the russeted skin, the walls of the peppers were thick and healthy looking.

Despite the damaged skin,
the walls of the peppers were
thick and healthy looking.

If you notice the damage early on (and recognize it as mite damage), you can control cyclamen mites with a miticide such as Bonide Mite-X and still have a good harvest later in the season.

Even though these mites did a lot of damage to our pepper crop, I must say it was pretty interesting to learn about them. It’s amazing to me that such a tiny critter could cause such dramatic abnormalities in the peppers and their foliage!

I’m just trying to look on the positive side!

Until next time – Happy Gardening!

Advertisements

Read Full Post »

Sad looking tomato plants

I'm pretty sure these Rutgers tomatoes are supposed to be bigger than 2" in diameter!

I’m pretty sure these Rutgers
tomatoes are supposed to be
larger than 2″ in diameter!

My tomatoes are a disaster this year!

Their growth is slow and they are not producing many flowers or fruit. Plus, the fruit that has formed is way smaller than it should be. It’s very disappointing!

I planted about 40 plants which included 9 different varieties, most of which are heirlooms because they are so delicious. Normally by this time of the season, the plants would be lush and full and looming over the top of our 6 foot trellises. There would also be lots of beautiful full-sized tomatoes with many more coming on. Not so this year!

The season started out on a downside when, within a few days of planting out my transplants, we noticed some severe cupping and curling of the foliage especially on the youngest leaves. When I saw it I immediately thought – classic 2,4-D herbicide injury! I wish I had taken some pictures of the damage.

Tomato injury caused by 2,4-D

Tomato injury caused by 2,4-D

It affected all of the tomato plants. I also noticed 2,4-D injury on our grape vines which are growing on the hill above the vegetable garden. Tomatoes and grapes are especially sensitive to broadleaf herbicides. Even light exposures can result in injury to the plants. If an herbicide like glyphosate (Roundup) or one that contains 2,4-D or dicamba is applied in the vicinity of a vegetable garden, it can easily drift onto the plants. Herbicides can drift pretty far if caught by the wind! We hadn’t sprayed anything but we found out later that a neighbor had been spraying a product containing 2,4-D to control thistle in the field right beside our vegetable garden. The spray must have drifted onto our newly planted tomatoes.

Strike One!

 

The spindly vines have a lot of diseased foliage.

The spindly vines have a lot
of diseased foliage.

We planted our tomatoes and most of the rest of the garden on the 21st of May. June had higher than normal rainfall, often in the form of heavy thunderstorms. This wet weather led to disease problems, especially in our heirloom varieties which make up about 80 percent of what we grow. We always have some disease in our tomatoes that wipes out their lower branches but it never seems to affect their production much. This year it was much worse. I am pretty convinced that the herbicide injury weakened and stressed the plants and left them more susceptible to fungal diseases.

Strike Two!

 

Hornworm damage on the Better Boy tomatoes

Hornworm damage on these
small ‘Better Boy’ tomatoes

Though we never seem to have much insect damage on our tomatoes, we have had an occasional hornworm on the plants. So far this year, Eric has discovered two hornworms on the tomatoes but only after they had almost completely defoliated a couple of the plants and chewed a few of the tomatoes as well! They are well camouflaged and it took a bit of hunting before he found and squashed the two culprits. Hopefully there aren’t more lurking among the foliage.

Strike Three!

 

With all these strikes against them, the plants have suffered tremendously. The foliage is sparse and the stems are elongated and spindly. I think this is mainly due to the herbicide injury early in the season.

The 'Pruden's Purple' tomato on the right is deformed and cat faced but at least it is larger.

The ‘Pruden’s Purple’ tomatoes
are small and some are deformed.

Though the plants have slowly outgrown the damage and the new growth is fairly normal, the plants are stunted and few flowers are being formed. The fruit that has formed is mostly remaining very small. I harvested a few medium-sized ‘Cherokee Purple’ tomatoes but most were deformed with severe cat facing (another symptom of 2,4-D injury).

Some of the problem may be environmental, too. I have heard that other people are having similar issues with their tomatoes; slow growth and the production of very few tomatoes that are all small in size. It may just be a bad year for growing tomatoes!

Unfortunately, it doesn’t look like we will be harvesting very many tomatoes this year. We should have enough to enjoy fresh but I’m pretty sure we won’t get enough to can.

The pole beans are doing very well!

The pole beans are doing very well!

On the bright side, the pole beans are doing very well except for 2 or 3 poles where some critter has nipped off the lower leaves. The vines are still strong and producing lots of beans at the top. We planted Rattlesnake beans, a purple pole bean, and a new one for us – Lazy Housewife Pole Beans. Yum!

The cucumbers have also produced well this year. So far I’ve made 23 pints of my famous bread and butter pickles and still have plenty to slice up for my lunches and I’ve even given a bunch away! I’ll be making more pickles this weekend and freezing beans, too!

I’m just so sad about my tomatoes …

Until next time –
Here’s hoping your tomatoes are doing better than mine!

Read Full Post »

Emerging bean seedlings

Now that you have your seeds and you’ve decided which seeds to start indoors and which to direct sow, the question becomes, when do you plant?

Determining when to start seeds for transplants

Tomato seedlings growing under lights

Tomato seedlings growing under lights

Starting your seeds indoors at the right time will give you nice, healthy, transplant-size plants at the ideal planting time in the spring. The correct timing depends upon where you live (what your average last frost date is) and the type of vegetables you grow.

Cool season crops like broccoli, cabbage, and cauliflower are tolerant of colder temperatures and transplants can be placed out in the garden earlier than warm season crops.

In general, cool season crops for transplanting should be grown indoors for about 4 to 6 weeks, but they can be planted outdoors 2 or 3 weeks before the last frost date. For some, these crops can be started pretty soon!

Peppers grow slowly and should be grown for about 8 weeks before transplanting

Peppers grow slowly and should
be grown for about 8 weeks
before transplanting outside

Warm season crops should be grown indoors for about 6-8 weeks but they should not be transplanted into the garden until a week or two after the last frost date. It doesn’t do any good to plant warm season crops like tomatoes, peppers, and eggplant early because, if the soil and/or air temperature is not optimal, the plants will just sit and not grow much until it gets warmer. These plants need warm temperatures to spur growth.

Here is a link to calculate (by zip code) your average date of last 32°F temperature (50% column on the chart).

Johnny’s Selected Seeds has developed a chart that will give you a date range for starting your seeds indoors and also when it is best to transplant your seedlings outdoors. All you need to do is input your spring frost-free date. You might want to use a more conservative date for this – maybe the 20% column rather than the 50% (average date) column.

When to sow seeds directly in the garden

Root crops like carrots do best when direct-sown in the garden

Root crops like carrots do best
when direct-sown in the garden

The timing for direct seeding into the garden is really more dependent on the spring weather conditions and the temperature of the soil. In general, it is safe to sow seeds directly in the garden after the last frost date but most vegetable seeds have specific soil temperature requirements for germination. It’s not the air temperature but the soil temperature that is critical in seed germination. Seeds begin growing when the soil reaches the optimal temperature for germination.

Seeds can rot in the ground before they germinate if planted in soil that is too cold – a waste of time and money!

Peas can be planted early since they are more cold hardy plants. Pea seeds can germinate in soils as cool as 40°F; whereas cucumbers germinate best when the soil temperature is 70°F and will not germinate at all if the soil temperature is below 50°F.

As you can see, it can be really helpful to have a soil thermometer!

Your seed packets will often provide information on the optimal soil temps for germination and this is the best guideline to follow. Many seed websites, like Johnny’s Selected Seeds, provide detailed growing information including when to direct seed each variety.

A ball of soil too wet to break apart when tapped. Garden needs to dry out more!

A ball of soil too wet to break
apart when tapped. This garden
needs to dry out more!

A word of caution!
Never work in the soil when it is wet – even if the soil temperature is perfect for planting. Digging or tilling in wet soil (or very dry soil) can destroy its structure by compressing the soil particles tightly together so that the pore spaces that hold air and water are lost. This hinders aeration and drainage and can quickly turn good soil into something almost as hard and crusty as concrete.

It is very important to make sure your soil is dry enough before you get in there and tromp around in the garden. You can test this by taking a handful of soil and squeezing it into a ball. If the ball breaks apart when you tap it, the soil is dry enough to be worked.

Using Phenology to determine planting time

Rather than going by a certain calendar date, some gardeners use phenology to determine the optimal time for various gardening chores, such as planting, pruning, weed control, etc. Phenology is the study of the timing of certain events in nature (for instance, the swelling of buds or the appearance of flowers) in relation to weather and climate.

For generations, many farmers and gardeners have relied on these observations of nature rather than the calendar. Plants and animals don’t know when the first day of spring is or what the average date of last frost is but they do respond to changes in local temperature and precipitation and their responses can give us a pretty good idea of how spring is progressing (or not) in any particular year.

The flowering sequence of forsythia provides a timeline for spring gardening chores

The flowering of forsythia
provides a timeline for many
spring gardening chores

“Indicator plants” are commonly used as a guide for planting and other spring chores.

Lilacs have proven to be a good indicator plant but one of Andre’s favorites is forsythia.

He says …

  • When the forsythia are in bloom, it’s time to direct sow cool-season crops in the vegetable garden. These include: spinach, lettuce, peas, carrots, chard, beets, and radishes.
  • When the forsythia are in full bloom, it is time to prune your hybrid tea roses, floribunda roses, and grandiflora roses.
  • Before the forsythia petals drop, apply a pre-emergent herbicide to control crabgrass in your lawn.
  • When the forsythia petals begin to drop, cut your Buddleia (butterfly bushes) back to about 12″-18″ from the ground. Use this same timing for cutting back your Caryopteris and Vitex.
  • When the forsythia have finished blooming, you can safely plant potatoes.
Lilac are another good indicator plant

Lilacs are another good indicator plant

Here are some others:

  • When daffodils bloom, plant spinach, beets, onions, and kale
  • When apple blossoms drop their petals or the lilacs are in full bloom, plant bush beans, pole beans, cucumbers, squash, and corn
  • When peonies flower, transplant tomatoes, peppers, eggplant, and melons

Well, there you have it; a few good tips on when to do some planting!

Until next time –

Happy Planting!

Read Full Post »

Nothing better than fresh, home-grown vegetables.

The time has come to look through your favorite seed catalogs and make some decisions about what you want to grow this season!

Rattlesnake beans

Usually, I can only find my favorite
rattlesnake pole beans in catalogs!

These catalogs (and their websites) offer a much wider selection of vegetable seeds than you will see in most garden stores. So if you want some varieties that are a little out of the ordinary, ordering from a seed company is the way to go.

Of course you have your old tried and true favorites but every year there will be some exciting new varieties that are hard to resist and in most cases, you will only be able to find these new and different vegetable seeds in your catalogs or online.

Don’t procrastinate!

Order your seeds soon so they arrive in time to start some of your crops indoors to get a jump on the season.

Transplants vs. Direct-sowing

Confused about which seeds to start indoors and which are best to sow directly in the garden? There are advantages and disadvantages to each of these practices and the answer really depends upon the individual crop.

  • Plastic lids cover each flat.

    Indoors, you can control lighting,
    humidity, and temperature for
    optimal germination and growth

    Starting seeds indoors allows you to have more control over the growing environment.

  • Certain pest and disease problems that plague young seedlings in the garden are avoided when plants are started indoors.
  • Pre-emergence weed preventers can usually be used in areas of the garden where transplants will be set out but not where you plan on planting seeds. Read the label before using a pre-emergent to be sure it is safe for your transplants!
  • Replacing early season crops in the garden with started plants allows you to produce another crop quickly.
  • Transplants must be hardened off before planting in the garden. Direct-sowing avoids this.

Certain crops perform better when set out as transplants while others do better when the seed is planted directly into the garden soil.

Here are some general guidelines:

Eggplant seedlings grow under lights until it is safe to plant in the garden

Eggplant seedlings grow under lights
until it is safe to plant in the garden

  • Crops with rapid top growth and slow root growth, like corn, beans, squash, and melons, don’t transplant well and are generally more successful when seeded directly in the garden.
  • Crops with rapid root growth and slower top growth, such as tomatoes, eggplant, peppers, and celery, will do better when planted as transplants.
  • Root crops are more successful when they are direct-sown as they tend to be more flavorful, tender, and straight if they grow at a steady rate from germination to harvest. Transplanting interrupts this steady growth.

Cool-season veggies to start indoors:

Broccoli, cabbage, cauliflower, lettuce, Kale, kohlrabi, Brussels sprouts

Cucumber seedlings transplanted and mulched in the garden

Cucumber seedlings transplanted
and mulched in the garden

Cool-season veggies to direct-sow:

Peas, radishes, turnips, parsnips, beets, spinach, carrots, potatoes (from seed potatoes)

Warm-season veggies to start indoors:

Tomatoes, eggplant, peppers, celery

Warm-season veggies to direct-sow:

Beans, corn, okra, cucumbers*, squash, melons, pumpkins

* – Cucumbers can also be started indoors to get a jump on the season.

Next time …

When to start your seeds; both indoors and direct seeding in the garden

Until then – Happy Gardening and get those seeds on order!

Read Full Post »

Corn crop destroyed by critters

We have had more trouble with critters enjoying our garden this year than ever before!

It is being a challenge to say the least.

End of June - pre-woodchucks

End of June – pre-woodchucks

Healthy pole beans and sweet potato vines

Healthy pole beans and sweet potatoes

It started back in the spring when cucumber beetles infected many of my small cucumber plants with bacterial wilt. I lost probably 50 percent of my original crop before I realized what the problem was and sprayed the plants with Bonide Eight. I had to reseed and also buy some plants to replace the ones that were lost. I kept on top of them after that and ended up with a great crop of cucumbers until disease finally destroyed the vines in mid August. At least I was able to enjoy lots of delicious cucumbers and make lots of pickles!

Most of the lower leaves were eaten

Most of the lower leaves were eaten

Woodchucks have been the worst problem this year. Despite the fence and wildlife netting we have around the garden, somehow at least one managed to get in. We first noticed it when all the leaves of our sweet potato vines were chewed off. Then the lower leaves of the pole beans began to disappear! At least it didn’t bite off the growing tip of the bean vine and they continued to climb up the poles. The plants were just leafless at the bottom.

We searched the perimeter of the garden and found a spot or two where it looked like some critter might have been getting under the fence. In those areas, we took some old fencing, bent it at a right angle, and pinned it down so that it extended about 2 feet out along the ground on the outside of the main fence. We hoped that would do the trick.

The beans had begun to recover by the time I took this photo

The beans had begun to recover
by the time I took this photo

After that, all was well for a while … until one day when Eric noticed that the leaves along the top of the bean trellis were being eaten! Our bean trellis is sort of like a pergola made out of bamboo poles. There are two rows of 8 uprights and then bamboo cross pieces join the two rows along the top. This allows the vines to grow between the poles at a manageable height (once they reach to top of the poles) so that I can easily reach the beans to pick.

It’s a great system but we were baffled as to how the foliage at the top was being eaten! Certainly if a woodchuck tried to climb the poles to get at the top leaves, they would have knocked the poles over or at a minimum torn down many of the vines in the process. Plus, I don’t think the cross pieces could support even the weight of a small woodchuck. Yet the leaves were chewed right off!

The only critter we could think of that might be able (and willing) to do this was a squirrel. Squirrels have been enjoying the foliage and flowers of the petunias on our deck for years. Actually, they have recently switched to the coleus and tomato leaves since there are no petunias left! So it seems entirely possible that squirrels are the bean robbers. How in the world could you keep them out?

They left us only the cobs!

They left us only the cobs!

A few weeks later just as the Silver Queen corn was beginning to ripen, we went out to the garden and found that about two thirds of the corn in the Three Sisters garden had been pulled down and the ears were chewed down to the cob. Normally I would blame this on raccoons but I’m wondering if it was the woodchuck(s) again. To make matters worse, since it’s the Three Sisters garden, when they tore down the corn, they also tore down the rattlesnake beans that were climbing up the corn stalks! We can’t see where they might be getting in – it’s very frustrating.

Destruction in the Three Sisters garden!

Destruction in the Three Sisters garden!

Not much left of this butternut squash!

Not much left of this
butternut squash!

After the corn, the woodchuck started in on the butternut squash. He just got one or two before we discovered this latest attack! Luckily we were able to protect the rest of the squash from being eaten. It was too early to harvest so Eric pulled the squash (still on the vines) together in groups and we were able to set them in plastic crates with another crate wired on top like a little cage. A few of the squash were off by themselves so I just put one crate upside down over them and pinned it down with landscaping pins. This seems to have kept the critters at bay – for now. Hopefully it will last until it’s time to harvest the squash.

Our improvised squash protection cage!

One of our improvised squash protection cages! So far so good!

Oh boy! What next? So far everyone has mostly left the tomatoes and peppers alone. Guess I’d better knock on wood! And at this point the beans seem to be recovering and producing new foliage and flowers. Perhaps the acorns and hickory nuts are beginning to ripen!

Until next time – Happy Gardening!

Read Full Post »

Tortoise beetle and larvae

Containers of Coleus, geranium, and herbs along the railing.

Containers of Coleus and geranium,
with herbs in pots along the railing.

We share our deck with lots of containers filled with beautiful plants. They add color and make it a more interesting place to sit and relax! Some of the pots are planted with flowers and foliage plants including some very colorful Coleus and others are planted with herbs that we snip fresh for cooking.

Two of the larger containers are planted with Juliet tomatoes. These miniature “Roma-type” tomatoes are our new favorite small tomato to grow instead of the cherry tomatoes we used to plant. In addition to the two on the deck, we also have two Juliet tomato plants growing in our vegetable garden. A tasty treat to munch on while working in the garden!

Juliet tomato

Juliet tomato

These delicious tomatoes are larger than a typical cherry tomato but bear just as prolifically. Their shape is oblong like a Roma tomato but they are smaller; growing up to 2¼” long and about 1¼” wide. They are meaty little guys and delicious straight off the vine (my favorite way to eat them), in salads, or for use in cooking. Yum!

Juliet is very crack resistant and stays fresh and firm on the vine longer than most cherry tomatoes. They also keep very well once picked but they always produce way more than we can eat fresh.

Juliet tomatoes are deliciously prolific!

Juliet tomatoes are deliciously prolific!

Last year in order to preserve the excess, we simply put them straight into freezer bags and froze them. Just straight off the vine – no processing required. Easy!

Whenever Eric made chili or soup or vegetable stew, he just pulled out a bunch of the frozen Juliet tomatoes, chopped them in thirds, and dropped them right in the pot. The skins can be fished out afterwards (or not) or you can thaw them a bit and slip the skins off before you cut them up. Simple and delicious!

Anyway …

Tomato leaf damage from the tortoise beetle

Tomato leaf damage from
the tortoise beetle

The other day when I went to pick some tomatoes off the plants on the deck, I noticed that several of the leaves were riddled with pretty large, very round holes. I’d never seen damage like this before. I’ve seen holes in leaves but never holes that were quite so uniformly round.

On further inspection, I found a few round, hard-shelled insects on the leaves. At first I thought they were some type of scale insect but when I poked one, it flew a short distance away and landed on another leaf – definitely NOT scale! Then there were some funky stationary ones that I assumed were either larvae or pupae.

Clavate tortoise beetle adult

Clavate tortoise beetle adult

This was a critter I was not familiar with. They didn’t seem to be doing much damage to the plant, just chewing lots of holes in a few of the leaves.

As it turns out, these were clavate tortoise beetles, Plagiometriona clavata. They do look a little like a turtle with a hard shell that covers not only their wings but their head as well. This particular species has a distinctive “teddy bear” shape on the shell.

Apparently these beetles are commonly found on plants in the solenaceous family which includes jimsonweed, nightshade, and also vegetable crops like tomato, pepper, and eggplant. We have four eggplants in a large container on the deck and I also noticed that a few of those leaves had these characteristic, round holes chewed in them. Tortoise beetles are also fond of morning glories which we happen to have planted in containers right beside our pots of Juliet tomatoes. Not surprisingly, many of the morning glory leaves are riddled with little round holes!

Tortoise beetle larva with fecal mass "shield"

Tortoise beetle larva with
fecal mass “shield”

The larvae of this beetle are unusual, too. They have an oval shaped, segmented body that is fringed with white spiny projections. The last segment of their body is modified with a forked projection which collects fecal material. This forked segment with the attached dried fecal mass is held over the body of the larva like a shield. It is thought that this may provide the larvae with some form of protection from predators through either camouflage or possibly as a type of repellent.

All-in-all, this is a very interesting and unique visitor to our plants and definitely not one that I had encountered before.

Always something new to learn in the garden!

Until next time – Happy Gardening!

Read Full Post »

Tomato harvest

Well, it’s that time of the year! The tomato questions are pouring in on our discussion board, Andre’s radio show, and over the phone and e-mails. At this point, the questions are mostly concerning problems with the foliage and just a few about the fruit.

One of the most recent discussion board posts brought up an issue that many gardeners may not be aware of …

“I have six different varieties of tomato plants planted in my raised bed. I noticed last week that the leaves had curled upwards. This week I noticed now that the leaves appear to be a little wilted as well as the blooms. The growth also seems somewhat stunted …

There are several things that can cause tomato leaves to curl but this combination of symptoms seemed consistent with herbicide injury.

Tomato injury caused by 2,4-D

Tomato injury caused by 2,4-D exposure

Herbicide drift can be a major problem for tomatoes because they are very sensitive to broadleaf herbicides. Even light exposures can result in injury to the plants. If an herbicide like glyphosate (Roundup) or a product containing 2,4-D or dicamba is applied in the vicinity of a vegetable garden, it can easily drift onto the plants. Herbicides can drift quite far when caught by the wind!

If they are exposed to only small amounts, the plants will usually survive and eventually outgrow the damage. Heavier exposures can be lethal.

Drift is not the only way that tomatoes can be exposed to herbicides.

  • If you spray your tomatoes with a fungicide or insecticide using a sprayer that has also been used to spray an herbicide, there may be herbicide residue left in the tank.
  • Herbicide damage can also occur if tomatoes are mulched with grass clippings from a lawn that has been treated with a weed and feed product or a broad leaf weed killer.
  • Lately, there have even been problems with plant damage resulting from mulches and compost that have been made from hay or manure taken from fields that had been sprayed with the herbicide Grazon.
Characteristic symptoms of glyphosate injury - yellowing at base of leaflets

Telltale symptoms of glyphosate injury –
yellowing at base of leaflets

In this case, as I learned from a later post, it turns out that a neighbor had been spraying herbicides in his yard and the drift had hit the tomato patch. Hopefully over time the plants will recover but flowering and fruit production may be delayed.

The bottom line:

  • Never spray herbicides in windy or breezy conditions
  • Use separate sprayers for herbicides and pesticides
  • Don’t mulch your vegetable garden with grass clippings if you have treated your lawn with a broadleaf herbicide

What else can cause tomato leaves to curl?

Physiological leaf roll is due to environmental stress factors

Physiological leaf roll is due to
environmental stress factors

Curled or rolled leaves can also be a physiological response by the plant to adverse weather conditions; too hot, too dry, too wet, too windy. The overall growth of the plant is usually not affected and the symptoms normally disappear when conditions improve.

Be careful not to over-water tomatoes. Overly wet soil conditions are often to blame for leaf roll.

Mulching your tomatoes will help maintain more even moisture content in the soil and also helps to maintain a more constant soil temperature.

There are several viral diseases such as curly top, yellow leaf curl, and mosaic virus that can cause curling of leaves, as well as stunted growth and pale leaves. There is no cure for these diseases and the plants cannot be saved.

Tomatoes with yellowing foliage and brown patches

Fungal disease is responsible for the majority of the tomato problems we face.

Fungal disease is responsible for the
majority of the tomato problems we face.

Some of the most common tomato problems are caused by fungal diseases. The tomato blights (early blight and late blight), as well as some of the wilt diseases and leaf spot diseases can be devastating to tomato crops. The first symptom is normally the yellowing of the older, lower leaves and branches.

Fungal spores that cause these diseases are found in the soil and on plant debris left in the garden. It is very important to rake up and remove old plants, fallen leaves, and rotting fruit from the garden at the end of the season. This important “housekeeping” task will help to reduce the incidence of fungal disease in the following season.

Mulching around your vegetable plants is another great way to reduce disease. This keeps soil (which may be filled with fungal spores) from splashing up onto the stems and leaves of your vegetable plants. Mulching the vegetable garden has so many benefits that it is worth doing every year!

If your tomatoes are showing signs of disease, prune off the diseased branches and throw them in the trash (do not compost them).

To prevent the disease from spreading to healthy foliage, spray the plants with a fungicide that is listed for use on edibles (Bonide Copper Fungicide, Mancozeb, or Fung-onil). Sometimes it’s good to alternate different fungicides.

Always read and follow the label directions!

Here are a few more tips to help you avoid (or deal with) tomato problems this season. Here’s to a great harvest!

Until next time – Happy Gardening!

Read Full Post »

Older Posts »

%d bloggers like this: