Take Caution to Curb Cucurbit Leaf Crumple Virus

Cucurbit leaf crumple virus
Photo by David Riley

Disease Specs

Cucurbit leaf crumple virus is a begomovirus that was first reported in squash in Florida in 2006. It hit watermelon growers around Southwest Florida especially hard this past spring.

Identification

Cucurbit leaf crumple virus (CuLCrV) usually starts in small patches in the field with new leaves showing yellowing. The yellowing pattern is unique and in early stages of infection appears between the veins.

As the disease progresses, the yellowing of the leaves will spread to the leaf margin. A tell-tale symptom of CuLCrV infection is crumpling of the leaves. Eventually, leaves develop unusual twisting combined with thickening, crumpling, and yellowing.
New leaves on runners can be severely infected with crumpling, which is readily noticeable. Unlike squash, which is severely damaged, watermelon plants may seem to recover from infection only for symptoms to rebound.

On yellow squash and zucchini, symptoms include thickened and distorted leaves, which become curled and crumpled in appearance. Zucchini fruit do not show obvious symptoms, but the fruit of yellow squash become streaked with green, making them unmarketable.

Survival and Spread

CuLCrV can infect most cucurbits and also is known to infect beans. As with other begomoviruses, this virus is transmitted in a persistent manner by the silverleaf whitefly, Bemisia tabaci. Whiteflies must feed for a minimum of 30 minutes on an infected plant and can only transmit the virus after a delay of 6 to 8 hours. Once the whitefly can transmit the virus, it can continue to do so for days.

The disease is common in areas where both horticultural and agronomic crops are grown close to each other, especially if there is poor whitefly management on any of these crops.

The virus cannot be transmitted mechanically and is unlikely to be transmitted through seed.

Management Methods

Management of CuLCrV is like the management of other begomoviruses. Virus and whitefly-free transplants should be used. Growers should avoid planting near older, whitefly-infested crops. Use of UV-reflective mulches, which repel migrating whiteflies in the first few weeks of the crop, can help delay the introduction of virus. Fields should be maintained weed-free, as they can be hosts for whiteflies, and can interfere with thorough coverage of insecticides applied for whitefly control.

Soil and drip-applied systemic insecticides are important tools for providing early and mid-season protection from whiteflies. A treatment window of 4 to 5 weeks should be used to plan insecticide rotations for whitefly management. For example, cucurbits could be treated at planting with Verimark (cyantraniliprole, DuPont), followed by a foliar application of Exirel (cyantraniliprole, DuPont) a few weeks later. A neonicotinoid could be applied through the drip at week five followed by a foliar application of Sivanto (flupyradifurone, Bayer CropScience).

Insect growth regulators Knack (pyriproxifen, Valent U.S.A.) and Courier (buprofezin, Nichino America) will reduce the number of viable whitefly eggs and prevent nymphs from completing development. Biopesticides, including insecticidal soap and Beauvaria bassiana, can help reduce whitefly numbers when used repeatedly.

Topics: , , , , ,

Leave a Reply

Cucurbits Stories
Apples & Pears
June 19, 2017
Bee-ware: New Resources Released for National Pollinator Week
New videos, webinars available during week-long observance. Read More
Crop Protection
June 7, 2017
Field Scouting Guide for Squash Powdery Mildew
Learn how to spot and treat a pest that impacts all cucurbits. Read More
Purple nutsedge on tomato plants
Cucurbits
June 6, 2017
Scientists Zone in on Precision Weed Control
Surgically placed fumigants at the base of promising pest management method for vegetable growers. Read More
Alternaria Leaf Spot of Cucurbits
Cucurbits
April 19, 2017
Alternaria Leaf Spot Awareness Can Save Your Cucurbit Crops
Learn how to identify, the survival and spread, as well as management methods for this malady. Read More
Crop Protection
March 10, 2017
Nematicide Now Available in California, Arizona
Velum One from Bayer also suppresses foliar diseases, increases yields. Read More
Cucurbits
March 8, 2017
How Steam Helps Remove Pathogens on Cantaloupes
The technique also may effectively sanitize watermelons, honeydews, cucumbers, and baby carrots. Read More
Cucurbits
January 20, 2017
Renowned Researcher Margaret McGrath Receives Cornell’s Excellence in IPM Award 
A plant pathologist, McGrath’s expertise has helped both organic and conventional growers fight late blight, downy mildew, and others.  Read More
Cucurbits
January 8, 2017
13 of the Latest Watermelon Varieties [slideshow]
Browse this slideshow for more information on 13 watermelon varieties you need to know in 2017 from the nation’s leading seed breeders and Read More
Anthracnose on cucumber
Cucurbits
December 22, 2016
Stay Alert to Anthracnose of Cucurbits
Learn how to identify, the survival and spread, as well as management methods for this destructive vegetable disease. Read More
Cucurbits
December 20, 2016
3 New Fungicide Product Options for Vegetable Growers
Unique modes of action the main feature of modern chemistries. Read More
Crop Protection
November 30, 2016
The Effect Of Soil Fertility On Fusarium Wilt In Watermelon
Ongoing research sheds light on the role soil health plays in the severity of the deadly pathogen. Read More
Crop Protection
November 8, 2016
The Effect Of Soil Fertility On Fusarium Wilt In Watermelon
Ongoing research sheds light on the role soil health plays in the severity of the deadly pathogen in watermelon crops. Read More
Diamondback cucumbers
Cucurbits
October 31, 2016
7 Squash And Cucumber Cultivars To Consider
Get the lowdown on several of the latest varieties making a name for themselves in the marketplace. Read More
Belmont watermelon from Sakata
Cucurbits
October 27, 2016
9 Melon Varieties To Keep In Mind
View some of the latest watermelon and cantaloupe varieties making an impact on the market. Read More
Crop Protection
October 25, 2016
Vegetable Grafting Facility Gears Up For Increased Production
The Tri-Hishtil vegetable grafting facility in North Carolina hopes to double grafted plant production by next year. Read More
The Latest
Cucurbits
September 6, 2017
9 Zucchini and Other Squash Varieties Yo…
Looking for a new squash to add to your production mix? Check out these varieties! Read More
Cucurbits
July 13, 2017
Scientists Keying in on Sweeter and Stro…
New study shows grafting can give growers an upper hand on soilborne disease threats. Read More
Cucurbits
June 20, 2017
Take Caution to Curb Cucurbit Leaf Crump…
Learn how to identify, the survival and spread, as well as management methods for this disease. Read More
Apples & Pears
June 19, 2017
Bee-ware: New Resources Released for Nat…
New videos, webinars available during week-long observance. Read More
Crop Protection
June 7, 2017
Field Scouting Guide for Squash Powdery …
Learn how to spot and treat a pest that impacts all cucurbits. Read More
Cucurbits
June 6, 2017
Scientists Zone in on Precision Weed Con…
Surgically placed fumigants at the base of promising pest management method for vegetable growers. Read More
Cucurbits
April 19, 2017
Alternaria Leaf Spot Awareness Can Save …
Learn how to identify, the survival and spread, as well as management methods for this malady. Read More
Crop Protection
March 10, 2017
Nematicide Now Available in California, …
Velum One from Bayer also suppresses foliar diseases, increases yields. Read More
Cucurbits
March 8, 2017
How Steam Helps Remove Pathogens on Cant…
The technique also may effectively sanitize watermelons, honeydews, cucumbers, and baby carrots. Read More
Cucurbits
January 20, 2017
Renowned Researcher Margaret McGrath Rec…
A plant pathologist, McGrath’s expertise has helped both organic and conventional growers fight late blight, downy mildew, and others.  Read More
Cucurbits
January 8, 2017
13 of the Latest Watermelon Varieties [s…
Browse this slideshow for more information on 13 watermelon varieties you need to know in 2017 from the nation’s leading seed breeders and Read More
Cucurbits
December 22, 2016
Stay Alert to Anthracnose of Cucurbits
Learn how to identify, the survival and spread, as well as management methods for this destructive vegetable disease. Read More
Cucurbits
December 20, 2016
3 New Fungicide Product Options for Vege…
Unique modes of action the main feature of modern chemistries. Read More
Crop Protection
November 30, 2016
The Effect Of Soil Fertility On Fusarium…
Ongoing research sheds light on the role soil health plays in the severity of the deadly pathogen. Read More
Crop Protection
November 8, 2016
The Effect Of Soil Fertility On Fusarium…
Ongoing research sheds light on the role soil health plays in the severity of the deadly pathogen in watermelon crops. Read More
Cucurbits
October 31, 2016
7 Squash And Cucumber Cultivars To Consi…
Get the lowdown on several of the latest varieties making a name for themselves in the marketplace. Read More
Cucurbits
October 27, 2016
9 Melon Varieties To Keep In Mind
View some of the latest watermelon and cantaloupe varieties making an impact on the market. Read More
Crop Protection
October 25, 2016
Vegetable Grafting Facility Gears Up For…
The Tri-Hishtil vegetable grafting facility in North Carolina hopes to double grafted plant production by next year. Read More