89 articles tagged "Cucurbits".

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…]


In a separate article in this issue, I discussed management of powdery mildew with conventional fungicides.  Here I would like to talk about powdery mildew management of cucurbits with organically approved products.  I will describe two studies, one with all organically approved products and a second with a combination of organic and conventional products.  All studies were conducted at the SW Purdue Ag Center in Vincennes, IN. The organic products discussed are defined as organic since they appear on the Organic Material Review Institute (OMRI).  There are other certifying agencies.  Be sure to check with your certifying agency before using any fungicide product.  As an example, the Champ DP® product used in 2010 is listed by OMRI as approved.  However, Champ WP® is not. In the 2010 study shown below, zucchini of the variety Raven F1 were planted in the certified organic plot managed at the SW Purdue Ag Center.  Organic products[Read More…]


Anthracnose on watermelon fruit, caused by Colletotrichum orbiculare, is typically round and sunken. (Photo by Dan Egel)

​Late in the 2015 season, I observed some unusual symptoms of anthracnose on watermelon fruit. I wanted to discuss these symptoms, but first a little background of cucurbits. An extension bulletin on this subject may be found at https://www.extension.purdue.edu/extmedia/bp/bp-180-w.pdf. Anthracnose of cucurbits, caused by Colletotrichum orbiculare, is responsible for lesions on leaves, stems and fruit. Crops affected include cucumbers and cantaloupe, however, watermelon is the host most often affected in Indiana. Although lesions on leaves and stems can cause significant loss, it is the lesions on fruit that cause direct yield losses. Lesions on watermelon fruit tend to be close to the ground where the fruit tends to stay wet. These lesions are typically round, sunken and orange to salmon colored (Figure 1). However, the lesions I observed toward the end of the 2015 season differed from the typical. Instead of regular round lesions, the symptoms I observed on the bottom of affected watermelon were[Read More…]


Solid green stems on fully mature pumpkins make a quality jack-o-lantern. (Photo by Liz Maynard)

​Pumpkin season is here. Keeping up with best management practices through harvest and storage will help the year wrap up on a good note. The steps below are a reminder of actions that can make a difference. Handle fruit as little as possible. Harvest fully orange and healthy pumpkins. Half-orange pumpkins may turn orange but quality and storage life will be reduced. Use a sharp knife or loppers to cut pumpkins from the vine. Leave stems long enough for an attractive product. Carry the pumpkin like a ball, not by the stem, or ‘handle.’ Brush off soil that sticks to the pumpkin. If pumpkins are washed, include a labeled sanitizer in the wash water and dry pumpkins before storage. Place pumpkins carefully in crates, bins, or trucks, so that the stem of one pumpkin doesn’t damage the rind of another. Watch for and avoid (or pad) sharp edges that could[Read More…]


Photo by Dan Egel

I have observed this disease in several pumpkin fields this year. It is not clear to me why this disease seems to be more widespread compared to recent seasons. However, it makes sense to review Plectosporium blight here. Plectosporium blight is usually not a serious disease. The occurrence of this disease is usually sporadic. However, when it occurs, it can cause yield loss if left uncontrolled. Older literature may list this disease as Microdochium blight. Plectosporium blight can be recognized from the light tan lesions on stems and leaf petioles. Lesions may also occur on the fruit, although these symptoms are less common. Yield loss is most often caused by lesions on the stem adjacent to the fruit—the pumpkin handle. Yellow squash and zucchini squash are also affected. Lesions are often individually spindle shaped. When these lesions occur in large numbers they can give a light gray or white appearance to[Read More…]


​When used as a verb, to rogue means to get rid of items that don’t conform to a certain standard. In plant pathology, the word rogue is used to describe a technique whereby diseased plants are removed or rogued to slow the spread of disease. I’d like to describe the practice as it might be used to manage Phytophthora blight of pumpkins. The practice works like this: Under conducive conditions, Phytophthora blight spreads quickly from leaf to leaf and from plant to plant. From a single diseased pumpkin plant, an entire field can become infected. But what if one could rogue the few symptomatic plants at an early stage in the disease epidemic? Would this slow the spread of Phytophthora blight? In theory, yes. If one were able to rogue all of the diseased plants in a field, the disease could be slowed. It would be similar to sending sick children home from a classroom; the disease should[Read More…]


Vegetable Crops Hotline - Department of Horticulture and Landscape Architecture 625 Agriculture Mall Dr. West Lafayette, IN 47907

© 2017 Purdue University | An equal access/equal opportunity university | Copyright Complaints | Maintained by Vegetable Crops Hotline

If you have trouble accessing this page because of a disability, please contact Vegetable Crops Hotline at guan40@purdue.edu.