67 articles tagged "Tomato".

Figure 1. Galling of tomato roots infested by root-knot nematode.

In a recent grower visit in southwest Indiana, we saw a severe root-knot nematode infestation on high tunnel tomatoes. Soil fumigation is by far the most effective approach to control nematodes, but many soil fumigants are not labeled for greenhouse (high tunnel) use. In addition, the types of equipment that used for soil fumigation are often hard to fit into high tunnels. Considering the constraints, this article focuses on cultural practices to control root-knot nematodes that can be easily adopted by small-scale, high tunnel growers. Root-knot nematodes are small, colorless roundworms that dwell in the soil. They penetrate into plant root in the juvenile stage. Once they find a favorable location in plant tissues, they stop moving. Infested root cells start swelling and form galls that are the characteristic symptom of root-knot nematode infestation (Figure 1.). Infested roots fail to absorb water and nutrient resulting  in stunted growth, yellowing and[Read More…]


Southern blight canker at the base of a pepper plant. Tomatoes can also be affected by this disease.

Southern blight of pepper and tomato thrives under hot, dry conditions. Usually, such conditions are more likely in August. Production under tunnels may contribute to the dry conditions that influences southern blight. This article will discuss the symptoms, biology and management of southern blight of tomato. Southern blight has a wide host range affecting many vegetable, field and ornamental crops. Tomato is the most important host. The disease is caused by the fungus Sclerotium rolfsii. This fungus is related to the one that causes white mold.The first symptom one is likely to observe of southern blight is plant wilt. At the base of the plant, one is likely to notice a canker with sclerotia that may be as large as a sesame seed (Figure 1). These sclerotia are survival structures for the fungus and allow the disease to occur in the same location years later. The sclerotia for southern blight are round,[Read More…]


After harvest, storing vegetables in optimal conditions is important to ensure the whole season’s hard work has paid off. This article discusses the optimum storage conditions for tomato, pepper, cucumber, watermelon, cantaloupe and sweet corn. Tomato Ideal storage conditions for tomatoes depend on the maturity stage of picking. If tomatoes are picked at mature green, store them in 66 to 70°F with 90 to 95% RH would encourage uniform ripening. Temperatures above 81°F reduce intensity of red color and reduce fruit shelf-life. Green tomatoes are chilling sensitive. If the temperature is below 55°F, fruit may develop chilling injury. Red tomatoes are safe to store at 50°F, however, flavor and aroma may be negatively affected compared to storing them at 55°F. Pepper Optimum storage condition for peppers is 45 to 55°F with 90 to 95% RH. Temperatures lower than 45°F may cause chilling injury. Colored peppers are in general less chilling[Read More…]


Figure 1. Initial symptom of blossom end rot on pepper.

In the past few weeks, we have received several reports about blossom end rot on tomatoes and peppers as the crops start to set fruit. Blossom end rot is a physiological disorder (not an infectious disease) that commonly occurs on tomatoes and peppers. Initial symptoms of the physiological disorder include dark green or brown water-soaked leisure occurring on the bottom of the fruit (Figure 1). The lesion then expands into sunken, leathery brown or black spots (Figure 2 and 3). In severe cases, the lesion can expand to half size of the fruit. The symptoms on tomatoes can be observed on fruit from fruit set to fruit the size of golf balls. Fruit on the same cluster tend to show symptoms simultaneously. On peppers, the symptoms are more likely appear during fruit expansion. The affected fruit often change color prematurely. Under moist conditions, opportunistic molds might develop on the affected tissues[Read More…]


Figure 1. Yellowstriped armyworm on tomato leaf.

We are seeing small caterpillars feeding on tomato leaves in high tunnels at Pinney Purdue. The first sign may be feeding partially through the leaf, or ‘windowpane’ feeding, or small holes on the leaf. By turning the leaf over we find a yellowstriped armyworm or hornworm (Figures 1 and 2). In the morning, we find moths clustered along the hipboard at the top of the sidewall (Figure 3). See Rick Foster’s articles in this issue for information on control.  


Figure 1. Hornworm feeding on tomato leaves in a high tunnel.

One of the most impressive insect pests that we deal with on vegetables are the hornworms (Figure 1 and 2). These two species, tomato and tobacco hornworm, can reach up to 4 inches long and consume massive quantities of foliage and fruit. In recent years, we have seen damage in high tunnels that is more serious than we normally see in field situations. The good news is that despite their size, hornworms are relatively easy to kill. A wide variety of insecticides will control them. See pages 143-44 in the Midwest Vegetable Production Guide for choices. As with most pests, it is better to treat when the hornworms are small because they are easier to kill and because you can avoid most of their damage. Hornworm damage is usually fairly easy to see, either because of the defoliation or the frass (insect poop) that they leave behind. So, scout regularly[Read More…]


I have received some reports of Colorado potato beetles damaging both potatoes and tomatoes, including tomatoes in high tunnels. Both the adults and larvae are voracious feeders. As with most pests, it is best to get potato beetles under control before the populations get too high. Also, killing small larvae is easier than killing large ones, so spraying earlier will provide better control. We have had numerous reports of resistance to the pyrethroids in Indiana, so I generally don’t recommend those products. If you try one and it works, then you probably don’t have a resistant population at this point. For most of the state, I recommend one of the following products, Admire Pro®, Agri-Mek®, Assail, Coragen®, Exirel®, Radiant®, and Rimon®. Note that Coragen® and Radiant® cannot be used in high tunnels.


White mold or timber rot of tomato causes a light brown area on the stem and a wilt of the plant.

White mold has a large host range including tomatoes (where it may be referred to as timber rot), cucumbers, lettuce and snap beans as well as many more. In this article, I will concentrate on white mold on tomatoes in a greenhouse situation. Although white mold will occur in a field situation, this disease is more common in a greenhouse due to the higher relative humidity than in a field situation. Perhaps the most common symptom of white mold of tomato is the light brown area on the lower stem (Figure 1 and 2). This brown area is essentially dead and will result in the wilt and death of the plant above that point. Either on the outside of this dead area or inside the stem, dark, irregularly shaped fungal bodies can usually be found. These fungal bodies (known as sclerotia) are diagnostic of white mold. Recently, I had a complaint of severe[Read More…]


Figure 3: Mottling of a tomato leaf caused by tomato spotted wilt virus.

Tomato spotted wilt virus can cause stunting (Figure 1), necrotic ring spots (Figure 2), mottling (Figure 3) or chlorosis (Figure 4). In Figure 5, a pepper plant is shown with a ring-like lesion due to tomato spotted wilt virus. Figure 6 is a photo of a pepper transplant with mottled lesions due to impatiens necrotic spot virus. Both TSWV and INSV can cause symptoms on many hosts including ornamentals. Figure 7 is a photo of INSV symptoms on begonia. For more information about the biology and management of these diseases see here.


A tomato leaf with necrotic rings caused by tomato spotted wilt virus.

While many virus diseases affect pepper and tomato plants, in the Midwest, the most common virus diseases of these two crops are tomato spotted wilt virus (TSWV) and Impatiens necrotic spot virus (INVV).  These diseases are usually observed in greenhouse or high tunnel situations. The two viruses, TSWV and INSV are closely related. In fact, at one time, they were both considered TSWV. Therefore, the symptoms, biology and management of these two diseases are similar. This article discusses the symptoms, biology and management of these two diseases. Both TSWV and INSV affect many hosts, including vegetables and flowering ornamentals. Symptoms vary according to host, stage of plant affected and environmental conditions. Both diseases can cause stunting, yellowing, necrotic rings, leaf mottle and more. Figure 1 shows a tomato leaf with necrotic rings caused by TSWV. Figure 2 shows a pepper transplant with ring spots caused by INSV. Additional symptoms may[Read More…]


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