104 articles tagged "Cucurbits".

The cool, wet weather we are experiencing is perfect for the root and seed maggots, namely cabbage maggot, onion maggot, and seedcorn maggot. One way of avoiding damage from these pests is to wait until the soils warm up to 70o F before planting, but that is not always possible. The use of row covers early in the season can physically prevent the flies from being able to lay their eggs on the soil near the base of the plants. There are some insecticides available, which vary by crop. Lorsban®, for the crops on which it is labeled, is probably the most consistent of the available insecticides. Capture LFR® has shown decent efficacy on melons and other crops. Melon growers who are putting Admire Pro® or Platinum® on as a soil drench at planting should not expect any control of seedcorn maggots from those applications.


Gummy Stem Blight – this fungal disease causes dark brown leaf spots, however, the diagnostic feature of this disease is the water soaked lesion that is often formed under one of the seed leaves (cotyledons). Such lesions often start at the point where the seed leaf joins the stem (hypocotyl) and do not extend to the soil line (Figure 1). In time, these lesions turn a light brown in color and appear ‘woody’. If one inspects the woody stem closely, it is possible to see dark specks imbedded in the stem—these are fruiting bodies of the fungus and will exude numerous spores when wet. Gummy stem blight affects both cantaloupe and watermelon. The fungus that causes gummy stem blight may be seed borne. The fungus may also survive on the residue left on contaminated transplant trays, the greenhouse floor or bench. Gummy stem blight may spread rapidly from plant to[Read More…]


Every year since 1980, we have conducted watermelon and cantaloupe variety trials at Southwest Purdue Agricultural Center. In 2016, our variety trials include 44 standard seedless watermelons, 12 cantaloupes, 4 mini-sized seedless watermelons, and 5 seeded watermelon varieties. Seeds have already been planted in the greenhouses and our target date for transplanting in the field will be the week of May 9th. The fruit will become ripe around the middle of July. If you are interested in observing how each variety performs during the season, don’t hesitate to come to visit us and witness the plots first hand. We will continue to present the results of our variety trials, as in the past, at the annual meeting held at the Southwest Purdue Ag Center in late November or early December but don’t miss the opportunity to visualize them during the growing season. In the winter meeting, we will discuss yield[Read More…]


I have never had as many questions about how to use MELCAST as I did in 2015. The interest in this program is growing both here in Indiana and nationally. Read on to find out how to apply fungicides according to the weather and perhaps save money in the process. MELCAST (MELon disease foreCASTer) is a weather-based disease-forecasting program for cantaloupe and watermelon growers developed By Dr. Rick Latin at Purdue University. Instead of using a calendar based fungicide application program where one applies fungicides every 7 to 14 days, the MELCAST program lets growers apply fungicides when the weather is most conducive to disease. The diseases for which MELCAST may be used for are: Alternaria leaf blight, anthracnose and gummy stem blight. Details are listed below or in the extension bulletin, Foliar Disease Control Using MELCAST, BP-67-W. Download the bulletin at http://www.extension.purdue. edu/extmedia/BP/BP-67-W.pdf or contact Dan Egel for a[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.      


The herbicide Chateau SW® is labeled for several vegetable crops including asparagus, mint, onion, and sweet potato. Recently, several growers asked Purdue University whether this product could be labeled in Indiana for cucurbit production. The answer is that Chateau® is not and will not be labeled for Indiana cucurbit production. We want to use this opportunity to explain why Chateau® will not be available for use by cucurbit growers in Indiana. The reason that the product Chateau® came to the attention of cucurbit growers in Indiana is that in other states Chateau® is available for use. These states include Florida and Georgia. The manner is which Chateau® is labeled in these other states is via third party indemnification. That is, the company that registers Chateau® makes an agreement with a grower’s organization in that state to limit liability for the registrant, Valent U.S.A. Valent U.S.A. has stated that they will[Read More…]


Three species of seed and root maggots attack vegetables in Indiana. The seedcorn maggot (Figure 1) feeds on seeds and seedlings of sweetcorn, cucurbits, lima and snap beans, peas, and other crops. Cabbage maggots can cause serious damage to transplants of cabbage, broccoli, cauliflower, and Brussels sprouts and make the fleshy roots of radishes, turnips, and rutabagas unmarketable. Onion maggots are pests of seedling onions, developing bulbs and onions intended for storage. Seedcorn maggot flies emerge in April and May and lay eggs preferentially in areas with decaying organic matter. Fields that are heavily manured or planted to a cover crop are more likely to have seedcorn maggot injury. Maggots burrow into the seed and feed within, often destroying the germ. The seeds fail to germinate and plants do not emerge from the soil, leaving gaps in the stand. When infested seeds germinate, the seedlings are weak and may die.[Read More…]


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…]


In recent years, many seed companies have begun using the neonicotinoid insecticide thiamethoxam (FarMore) as a seed treatment on cucurbit and other vegetable seeds. Thiamethoxam is a systemic insecticide that moves from the seed coat into the seedling and then moves throughout the plant. Research has shown that these seed treatments provide about 3 weeks of excellent control of cucumber beetles, aphids and other pests. Unfortunately, the systemic nature of the insecticide also results in residues being present in the pollen that could potentially be harmful to honey bees and other pollinators. Although these seed treatments are a good pest management tool, growers should be cautious in how they use them to avoid possible harm to pollinators. Our research has shown that cucurbits that are grown in the greenhouse for 4-5 weeks before being transplanted into the field, do not have enough of the insecticide left in the stem and[Read More…]


The last two summers, I have had pretty good fungicide trials for powdery mildew of pumpkin. Since all of the products trialed are now labeled or close to being labeled, I thought it was time to share this information with vegetable growers of Indiana. First, a bit of background about this disease. In Indiana, powdery mildew affects primarily pumpkin and cantaloupe.  The disease is easily recognized by the talc-like lesions on both sides of the leaf. (This article will help with diagnosis.) If left uncontrolled, the disease can cause loss of foliage, loss of yield and lower quality fruit. The fungus that causes powdery mildew, Podosphaera xanthii, does not require leaf wetness for infection of leaves, only high humidity. The optimum temperature for disease development is 68 to 81°F. P. xanthii may survive in crop residue as a resilient fungal structure, but the disease is so easily windborne, that crop[Read More…]


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