72 articles tagged "Tomato".

Planting density plays an important role in the optimization of labor efficiency and productivity of your high tunnel. For the purpose of this article I will focus on tomato which is commonly grown as a high value crop on small farming operations. Usually growers select varieties according to customer (market) preference and then try to combine that with other attributes such as ease of production, disease tolerance/resistance and productivity (yield). Consumer preference usually helps to determine the fruit color, size and shape, and the sweetness (soluble solids) of the tomato variety to be grown. The grower again is interested in earliness, growth habit (determinate and indeterminate), and ease of pruning, trellising and picking. Most growers in Indiana choose determinate varieties for high tunnel production, because it has limited growth and is easy to stake and allows for early production (short production cycle), with most fruit ripening before field grown tomatoes[Read More…]

Recent cool weather increases the occurrence of zippering on high tunnel tomatoes. We observed at least 20% of developing fruit (most on the first and second flower clusters) on the variety Mountain Spring showed the zippering symptoms in our high tunnel. A typical symptom of the disorder is a thin, brown, necrotic scar that starts from the stem end and extend fully or partially to the blossom end. The reason the symptom is called zippering is because transverse scars are along with the longitudinal scar that looks like a zipper (Figure 1). In more severe cases, the scar is open and reveal locule (Figure 2). In the initial stage, zippering is often observed with anthers adhering to the fruit (Figure 3), the attached anthers is believed to disturb fruit development and cause the symptom. Zippering symptom is more noticeable with cool weather. Optimum temperatures for tomato fruit set are 60-75°F (night) and 60-90°F[Read More…]

The recent cool and cloudy weather has influenced conditions in the field as well as in greenhouses and high tunnels. I have observed more Botrytis gray mold of tomatoes in greenhouses this spring than usual. This is due in part to the weather. This article will discuss this disease on tomatoes and some management options. Gray mold is caused by a fungus that attacks many types of vegetables and ornamentals. The fungus is not a strong pathogen and often starts on weakened or senescent tissue such as old flower petals. The gray mold fungus, Botrytis cinerea, may be a weak pathogen, but it is a good saprophyte, growing well on old crop debris and organic matter until a good plant host is available. Figure 1 shows a tomato leaf on which a flower petal has fallen. Since the gray mold fungus is sporulating on the flower petal, there is a[Read More…]

In a recent visit to a high tunnel, we observed a severe salinity problem on tomatoes. Approximately one month after planting , most tomato plants in the affected area had not sent out any new leaves. Roots did not grow at all (Figure 1).  After conducting a soil test, very high soluble salt level explains these symptoms. This article reviews the basics of soil salinity. Salinity describes salt content in the soil. Virtually all fertilizer materials are salts, but they vary in their effects to increase salt concentration in soil solutions. In a field situation, precipitation in the form of rain and snow tend to leach salts.  Since high tunnels exclude rain and snow, elevated salt levels are a common concern for high tunnel vegetable growers. Table 1 are the salt indexes of common fertilizers. If you are using a premixed fertilizer such as 12-12-12, check the fertilizer components on[Read More…]

Figure 1. Note stigma of tomato flower on the left was more exerted compared to flower on the right. In addition to temperatures, genetic factor, nutritional status and light might cause stigma exertion.

Maintaining temperature in the ideal range is very important for tomato fruit set. The optimum temperatures are 60-75°F (night) and 60-90°F (day). Studies showed that exposing plants to 3-h periods of temperatures above 104°F on two successive days may caused fruit set failure. Not only is the maximal temperature critical for fruit set, maintaining night temperature in the ideal range is also essential. Effects of high temperature on fruit set are primarily on the stage of pollen development, which occurs about nine days before flowers open. High temperatures also affects flower structure by causing stigma exertion that prevents pollen from successfully landing on the stigma (Figure 1). After pollination, pollen germination can be severely reduced at temperatures above 100°F. Preventing temperatures from reaching the extremely high level is important in high tunnel tomato production. Since biomass production and flower numbers are less likely to be affected by high temperatures compared to[Read More…]

Recently, this disease was observed in a greenhouse in Indiana. This article will serve as a review of this important disease. The symptoms of bacterial canker vary considerably. In most cases, the edges of the leaves may turn yellow and/or brown. That is, the margins of the leaves may become chlorotic and/or necrotic (Figure 1). This symptom, which is sometimes known as ‘firing’, may be more common in a field situation than in a greenhouse. Tomato plants may wilt as a result of bacterial canker. The inside of the stem of affected plants may be discolored brown (Figure 2). The fruit may have bird’s-eye spots-this symptoms is more common in field outbreaks.  In the greenhouse where this disease was recently observed, adventitious root development was observed on the stems of affected plants. That is, the stems may develop a ‘bumpy’ appearance where extra roots are starting to develop. However, this symptom may also develop from stresses[Read More…]

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We went through an unseasonably cold period in early April (Figure 1). In southern Indiana, a few high tunnel tomato growers have already planted their crops. These plants may need some extra help. In Vincennes, IN, we used row covers to cover the newly planted tomatoes in high tunnels the past few nights, our recorded lowest temperature was 37 °F under row covers. Plants all look good. However, the temperature is apparently too cold for cucumbers. The majority of the early planted cucumbers in our high tunnels were dead. We are waiting for the weather to warm up (soil temperature at least above 60 °F) to reset the cucumbers. Please let us know if you also ran into problems in the past a few days because of the low temperature. It might be issues in the greenhouse, the high tunnels, or even the field. We would appreciate you sharing your experiences with us.      

Lettuce is grown in channels using the Nutrient Film Technique

Travelling through Indiana last summer, I realized that many growers plant their crops in soil inside their high tunnels or greenhouses. Soilless production offers different benefits and challenges. This is the first article in a series focusing on soilless crop production in high tunnels and greenhouses. Today we are discussing Hydroponics. What is Hydroponics?  The word hydroponics technically means ‘working water’, derived from the Latin words “hydro” meaning water and “ponos” meaning labor. Hydroponics is a method to grow plants using a mineral nutrient solution, in water and without soil. Two types of hydroponics are commonly found: a) solution culture, and b) medium culture. Solution culture types include continuous flow solution culture (Nutrient Film Technique) and Aeroponics. Medium culture types include ebb and flow sub-irrigation, run to waste, deep water culture and passive sub-irrigation systems. History.  The first research published on the production of spearmint in water was conducted by[Read More…]

One way insects communicate with individuals of the same species is with pheromones. Pheromones are volatile chemicals released by an insect that usually can be detected only by individuals of the same species. There are a number of different types of pheromones, but the most common type is the sex pheromone. Usually the females will emit a tiny amount of a chemical that attracts the male to her and increases the likelihood of mating. Because the chemical is volatile, air currents carry it. The male detects the pheromone in the air with receptors on his antennae. He then flies upwind to find the source of the pheromone, a prospective mate. The chemical compositions of pheromones for a number of pest species have been identified and synthetic copies can be produced in the laboratory. Synthetic pheromones can be used in conjunction with traps to catch male insects. Listed below are some, but[Read More…]

Tomatoes grown in controlled environment are exposed to conditions that are different from their original habitats. As a result, varieties that are not specifically bred for greenhouse production may respond to the controlled environment with abnormal symptoms. One group of the symptoms is called edema. Bumps, galls or blisters develop on tomato leaves, petioles or stems (Figure 1). In severe conditions, it causes leaf curling, distortion and abscission (Figure 2). A couple of factors including high humidity, excessive water in the soil, air pollution, and low light condition could cause the symptom. Tomato varieties respond differently in susceptibility to the physiological disorder, and the primary contributing factors can also be different among tomato varieties. The most severe case of edema that we have observed so far is on tomato rootstocks including ‘Maxifort’. This is not surprising as most of the commercial tomato rootstocks are hybrid of wild tomatoes Lycopersicon esculentum[Read More…]

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