11 articles tagged "Squash".

Winter squash – butternut, acorn, and kabocha – in our downy mildew sentinel plot at Pinney Purdue were showing some wilted and stunted plants by late July (Figure 1). They are easily pulled up, the stem breaking off at ground level, revealing a brown stringy decayed-looking stem base (Figure 2). Sometimes there is a little whitish or maybe pinkish mold on the stem. I cut open a kabocha squash to look for squash vine borer larva and found sap beetles that seemed to be feeding inside the stem, but no vine borer (Figure 3). The sap beetles were clearly taking advantage of an opportunity, but not the cause of the wilt. Perhaps a borer had already come and gone. I used scotch tape to pick up some of the mold and put it on a slide to look at under the microscope. At 100X and 400X I saw among the[Read More…]


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Finally the time has come to plant warm season crops. Zucchini is a popular summer squash grown throughout Indiana and the United States. It always delivers a bounty of fruit. Yes, technically zucchini is a fruit (botanically classified as a modified berry) but as per the USDA it is listed under the ‘Vegetables and Vegetable Products” food group. Zucchini have a multitude of fruit colors and flavors. Therefore, this makes a great vegetable to present to consumers. Characteristics of zucchini – Typically, zucchini is non-vining and bushy but some varieties could have a creeping habit. Some varieties have prickly trichomes on both the stems and leaves. Male and female reproductive structures are produced on the same plant but in different flowers. The large yellow-orange unisexual flowers (a flower that possesses either stamens or carpels but not both) attracts bees, beetles and other insects to pollinate the flowers. The pollen is[Read More…]


Gowers always want to know which variety is the most suitable one for their farming location and market. I do understand the frustration of growers when looking online at all the varieties being sold by different vendors. There are a plethora of varieties available that have different fruit types and growth habits. Characteristics like potential yield and disease resistance are always important considerations for growers. Which variety will work best for my farming operation and market? During 2018, I attempted to address growers’ concerns and need for local variety performance data, hosting a zucchini field trial at the Throckmorton Purdue Agriculture Center/Meigs Horticulture Facility, Lafayette, Indiana. How was the evaluation conducted? Soil of the test plot comprised of a Toronto-Millbrook (47%) complex, Drummer (27%) and Starks-Fincastle complex (26%) (ranged from a silt loam to silty clay loam). The spring 2018 soil test showed 2.8% organic matter, pH 5.7, and 34[Read More…]


Figure 2. Squash bug nymphs (photo credit John Obermeyer)

Squash bug is the most consistent insect pest of squash and pumpkins and is the most difficult to control (Figure 1 and 2). The key to management is early detection and control of the nymphs. The adults are extremely difficult to kill. Foliar insecticides should be applied to control the nymphs when you have more than an average of one egg mass per plant. When you find egg masses, mark them with flags and check every day or two to see when they hatch. When many of the egg masses are hatching, that is the time to begin application. Since eggs are laid and hatch over an extended period of time, several applications may be required. Brigade®, Mustang Max® and Warrior® have provided excellent control.


With the start of pumpkin harvest, it is a good time to review important considerations for harvest and postharvest storage of pumpkins and winter squash (butternut, acorn and hubbard squash etc.). First, pumpkin and winter squash should be harvested fully mature to reach their optimal quality and fulfill their potential for long shelf lives. Characters indicating fruit maturity include loss of rind surface gloss, ground spot yellowing, and hardening of the skin to the level that it is resistant to puncture with a thumbnail. Except for some striped varieties, mature fruit should have solid external color. If fruit have to be harvested pre-mature because of plant decline, these fruit won’t store as well as mature fruit. The best practice is to harvest the fruit as soon as they are fully mature and then store under proper conditions. If mature fruit are left attached to the vines, it increases the chance[Read More…]


Figure 1. Squash bug and its eggs (photo credit John Obermeyer)

Squash bug is the most consistent insect pest of squash and pumpkins and is the most difficult to control. The key to management is early detection and control of the nymphs. The adults are extremely difficult to kill (Figure 1). Foliar insecticides should be applied to control the nymphs (Figure 2) when you have more than an average of one egg mass per plant. When you find egg masses, mark them with flags and check every day or two to see when they hatch. When many of the egg masses are hatching, that is the time to begin application. Since eggs are laid and hatch over an extended period of time, several applications may be required. Brigade®, Mustang Max® and Warrior® have provided excellent control.  


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…]


​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…]


​Downy mildew has been confirmed on jack-o-lantern pumpkins in Daviess and Jasper Counties and on acorn squash in LaPorte County. These are the first confirmed reports of this disease on Cucurbita pepo in Indiana in the 2015 season. There are unconfirmed (but reliable) reports of downy mildew on pumpkins in Parke,  Washington, and White Counties. This disease has also been observed on butternut squash (Cucurbita moschata) in Knox and LaPorte Counties and on giant pumpkins (Curbita maxima) in LaPorte County. Read more about this disease at ag.purdue.edu/arp/swpap/VeggieDiseasesBlog/Lists/Posts/Post.aspx?ID=48.


On July 22, I announced that downy mildew had been observed on watermelon in Knox County in southwestern Indiana. This article in the Vegetable Crop Hotline issue 603, https://ag.purdue.edu/hla/Extension/VegCropsHotline/Pages/Latest-Articles.aspx?article=118, describes the outbreak and management options. Downy mildew has now been reported on cucumber and cantaloupe in Knox and cucumber in La Porte County Indiana and pumpkin in Jasper County. Downy mildew has been observed on pumpkins in Mason County in central Illinois. In addition, several counties in Kentucky and Michigan have reported downy mildew, primarily on cucumbers. You may follow the development of downy mildew of cucurbits on this website http://cdm.ipmpipe.org/.


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