Cercospora leaf spot (CLS), caused by Cercospora beticola, is an important and emerging disease in beet and swiss chard production in New Jersey. Efforts to control this disease has become more difficult in the past few years in some areas of southern New Jersey. [Read more…]
Vegetable Crops Edition
Seasonal updates and alerts on insects, diseases, and weeds impacting vegetable crops. New Jersey Commercial Vegetable Production Recommendations updates between annual publication issues are included.
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June 20, 2022 Andy Wyenandt
Cucurbit powdery mildew control in 2023
Cucurbit powdery mildew (CPM), caused by Podosphaera xanthii, is one the most important diseases of cucurbit crops throughout the world. The pathogen is an obligate parasite, just like cucurbit downy mildew, meaning it needs a living host in order to survive. In northern regions that have a killing frost in the fall the pathogen will die out when the crop freezes. Not being able to overwinter, the pathogen must be re-introduced each spring or summer in the mid-Atlantic region. The pathogen accomplishes this by re-infecting cucurbit crops in the spring as they are planted up the east coast starting in Florida, then the Carolina’s, Virginia, and so forth. By late May, as soon as cucurbit crops begin to germinate in the mid-Atlantic region, the potential threat for potential powdery mildew infections begin. [Read more…]
June 15, 2022 Kris Holmstrom and Joe Ingerson-Mahar
Vegetable IPM Update 6/15/22
Sweet Corn
Low numbers of European corn borer (ECB) moths continue to be captured, and feeding in whorl stage corn is rising. The highest adult activity is currently Hunterdon County (see map below at right). ECB injury over 60% of plants infested has been found in southern Hunterdon County this week. While this level of feeding is unusually high, ECB has become something of a local phenomenon in NJ, and growers should not assume that feeding is below economic levels in their area. It is typical for feeding percentages to rise as the moth catch declines. We expect feeding to increase for the next 1-2 weeks before peaking.
Look for the characteristic “shot-hole” type of feeding (photo below at right) and consider treating when infested plants exceed 12% in a 50 plant sample. As plantings proceed to the pre-tassel stage, ECB larvae may be found in emerging tassels (see photo at left). It is a good idea to treat individual plantings as they move into the full tassel/first silk stage one time. This eliminates any ECB larvae that have emerged with the tassels as they begin to move down the stalk to re-enter near developing ears.
Useful insecticides for this particular application include synthetic 
pyrethroids (IRAC Grp 3), spinosyns (including OMRI approved Entrust) IRAC Grp 5), and diamides such as Coragen or Vantacor (IRAC Grp 28) or materials such as Besiege which include the active ingredient in Coragen. Synthetic pyrethroids alone should NOT be used for corn earworm (CEW) protection on silking corn. Control with these materials is very inconsistent.
The highest nightly trap catches of ECB for the week ending 6/15/22 are as follows:
| Sergeantsville 2 | Dayton 1 | Pedricktown 1 |
| Bellemeade 1 | Downer 1 | Pennington 1 |
| Califon 1 | Folsom 1 | Port Murray 1 |
| Crosswicks 1 | Milltown 1 | South Branch 1 |
June 11, 2022 Andy Wyenandt
Cucurbit Downy Mildew Alert – Cucumber – 6/11/22
Cucurbit downy mildew has been confirmed on cucumber in southern New Jersey. This is the first report of CDM in the state and region this growing season. All cucumber and cantaloupe growers should scout on a daily basis and initiate a preventative fungicide program. CDM was last confirmed on June 1 on cucumber in central North Carolina and on watermelon on June 9 in south central Georgia. Remember, some CDM isolates fall into Clade I which predominately infect watermelon, pumpkin, and squash, where other CDM isolates in Clade II predominately infect cucumber and cantaloupe.
For more information on CDM, the clades, and CDM control please click here.
Cucurbit downy mildew sporulating on the underside of an infected cucumber leaf.
June 8, 2022 Kris Holmstrom and Joe Ingerson-Mahar
Vegetable IPM Update 6/08/22
Sweet Corn
Low numbers of European corn borer (ECB) moths continue to be captured throughout the state. The highest adult activity is currently from Gloucester through Burlington counties (see map at right). Whorl corn is the primary target for egg laying, and injury well over the 12% threshold has been found in Hunterdon County this week. Feeding percentages in many areas have been relatively low, but this pest still poses a threat to plantings now approaching full tassel. It is typical for feeding percentages to rise as the moth catch declines. We expect feeding to increase for the next 1-2 weeks before peaking.
Look for the characteristic “shot-hole” type of feeding (photo below at right) and consider treating when infested plants exceed 12% in a 50 plant sample. As plantings proceed to the pre-tassel stage, ECB larvae may be found in emerging tassels (see photo at left). It is a good idea to treat individual plantings as they move into the full tassel/first silk stage one time. This eliminates any ECB larvae that have emerged with the tassels as they begin to move down the stalk to re-enter near developing ears.
Useful insecticides for this particular application include synthetic pyrethroids (IRAC Grp 3), spinosyns (including OMRI approved Entrust) IRAC Grp 5), and diamides such as Coragen or Vantacor (IRAC Grp 28) or materials such as Besiege which include the active ingredient in Coragen. Synthetic pyrethroids alone should NOT be used for corn earworm (CEW) protection on silking corn. Control with these materials is very inconsistent.
The highest nightly trap catches of ECB for the week ending 6/08/22 are as follows:
| Medford 3 | Centerton 1 | New Egypt 1 |
| Cinnaminson 2 | Clinton 1 | Port Murray 1 |
| Downer 2 | Eldora 1 | Sergeantsville 1 |
| Blairstown 1 | Milford 1 |
June 8, 2022 Melissa Bravo
Crop Progress and Hessian Fly Sightings
June 8, 2022 Salem County, NJ
Salem County has experienced nearly two weeks of ideal temperatures in the mid 80’s to low 90’s allowing for a considerable amount of soybean acreage to be planted, and hay acreage harvested. Rye for grain harvest is nearly complete and barley will soon follow. With a 72-hour forecast of one inch to one and a half inch expected, many producers have switched back to planting as the window to make dry hay closes.
Corn: Early planted corn is near canopy and in very good condition. Surface moisture is adequate but at this stage of rapid stem elongation, rain is needed to replenish the two inches of rain received at the end of May but less than a tenth of an inch in the last week. Overall, most of Salem County received in excess of 12 inches of rain in the last 90 days ending June 6, which is over an inch and a half more than the average for this period of the growing season and substantially more than the drought stressed crops in Cape May County that are experiencing a 75% deficit in moisture for the last seven days. Corn planted into standing rye and other late terminated cover crops is lagging behind tilled fields due to moisture competition and carbon sink, but overall flushes of seedling broadleaves are not present indicating preemergence programs are working effectively.
Soybeans: Full season soybean planting is nearly complete. Emerged beans are ahead of seedling flushes of pigweeds but behind giant ragweed in areas where ragweed is present. Expect amaranth species weed pressure to increase significantly after this weekend’s forecasted rain.
Wheat: Wheat is drying down rapidly and in overall good to excellent condition. In areas where irrigated wheat is already yellow and evidence of wind damage is visible, Hessian Fly is the most likely culprit as seen in this photograph taken in a dough stage field. Flowering canada thistle seen in wheat that will be double cropped with soybeans should be de-headed to prevent seed dispersal prior to harvesting. In enlarging patches, consider a spot-treatment (sacrificing soybean) of a growth regulator herbicide if prior treatments of glyphosate products have not limited spread.
About Hessian Fly: Mayetiola destructor (Say) is a grain pest in the Cecidomyiidae family. It is a major cause of wheat yield reduction around the world. The fly forms galls on the underside of wheat leaves that protect the feeding larva from efficacious applications of insecticides. In addition to wheat, Hessian fly can be found in rye, barley and in brome grasses (and reedscanary). Bromes are a major composition of the grasses in this area. Egg hatched occurred when temperatures were above 50 degrees earlier this season.
https://www.weather.gov/marfc/Precipitation_Departures
If producer’s noticed patches of dark green areas of wheat (barley) in the same fields now infested with flies or where lodging is increasingly evident, these are an indicator of where the larva were pupating.
Larval feeding after stem elongation causes lodging. Feeding damage can also cause failure to produce a seed head, and a reduce seeds per spike and light test weight. – Journal of Integrated Pest Management, September 2018 article.
The adult swarm seen today are emerging after fourteen days of ideal weather above 70 degrees Fahrenheit. Now that flies are present, they will lay eggs over the course of the next week.
Due to climate change, it is possible that there could be three emergences of Hessian Fly this year. Southern states see as many as six generations. Generally, in northern states past recommendations have suggested the fly has an emergence in the spring and again in the fall. But in southern states emergences occur in multiples of one, two three in spring, and again in fall. Which is where management strategies come into play. Knowing the number of emergences in our area can help producers calculate if delayed planting will assist with controlling a two brood a year emergence or if it is unlikely to help with multiples of brood emergences. Wind plays a major role in dispersal from infected fields to non-infected fields. Due to cover crop program planting dates for small grains, producers with Hessian Fly issues should talk to their local NRCS office to make sure program planting dates take into account the local Hessian Fly Free dates for fall of 2022.
What to do now: Producers can identify Hessian Fly by looking for swirling clouds of insects that look like white smoke coming out of the wheat canopy. Swatting the swarm will trap flies on the palm of the hand for easier identification. The female fly has a distinctive orange striping to her abdomen. Hessian flies are orange and black banded compared to the overall all orange appearance of wheat midges. At this stage, the flies have already pupated through the larval stage, which already damaged the wheat crop by tunneling into the stems. Most likely lodging is evident nearby.
What producers can do to plan for next year: Hessian fly was most likely introduced to North America in infected straw bedding. Straw from infested fields may still contain larva. The fly and larva are not considered a pest of stored grain. The larva pupate in the axis of the leaf stem. Cutting straw stubble below the leaf nodes and removing it from the field may help in management as the Hessian Fly larva overwinter inside a flax-seed like cocoon (puparia) at the base of infected plants. Plant resistant cultivars, delay planting dates if this year’s infestation is associated with an earlier planting date, destroy volunteer wheat, and manage brome grasses in field edges and within field when possible.
Hessian Fly Free Planting Dates in Southern New Jersey: “In Maryland, plant wheat following the Hessian fly-free date for your area. This date is approximately September 30 for the Hagerstown area and becomes progressively later as you move from the south and east in the state. The fly-free date is October 13 on the Lower Eastern Shore.” – Read more in 10 STEPS TO PROFITABLE WHEAT PRODUCTION in the Maryland Agronomy News.
Additional considerations for producers planting winter wheat – double crop soybeans-winterwheat: “Growers should avoid planting wheat into last season’s wheat stubble. Continuous no-tillage, wheat-double-cropped-soybeans may result in severe problems and should be avoided in Hessian fly problem areas.” – https://www.farmprogress.com/grains/hessian-fly-resistance-threat-southeast-wheat
Source information. For a detailed publication on Hessian Fly (Diptera: Cecidomyiidae) Biology and Management in Wheat visit Journal of Integrated Pest Management, (2018) 9(1): 14; 1–12 issue.
Salem County Producers, if you are seeing signs of Hessian Fly lodging, contact Melissa Bravo at the Salem County Extension Office so fields can be monitored in the fall to determine the Hessian Fly Free dates for this area.
