Month: August 2022

Late Summer Insect Tips 

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Late Summer Insect Tips
Emily Zobel, AgFS Agent, UME 

Remember to rotate modes of action from one spray to another and to rotate modes of action out every 30 days. Be sure to read the label. Not all materials are labeled for all crops, insects, or application methods. See the Mid-Atlantic Commercial Vegetable Production Recommendations Guide for more information (https://go.umd.edu/MidVegGuide).

Cole Crops/ Brassicas:  Check seedlings and new transplants of fall brassicas for caterpillar, and harlequin bugs feeding damage. For fresh-market cabbage, Brussels sprouts, broccoli and cauliflower, treat when 20% or more of the plants are infested with any species of caterpillar (imported cabbage worm, cross striped worms, cabbage looper, diamondback moth or armyworms) during seedling stage, then 30% infestation from early vegetative to cupping stage. From early head to harvest in cabbage and Brussels sprouts use a 5% threshold. For broccoli and cauliflower, use 15% at curd initiation/cupping, then 5% from curd development to harvest. If treatment is needed make sure to adjust your spray pattern such that spray is getting sideways to the undersides of leaves, particularly when using Bacillus thuringiensis and contact materials. Due to resistance development, pyrethroid insecticides (Group 3A) are not recommended for control of diamondback moths (Fig 1.). Remember to rotate between two modes of action within a 1 month period and among two different modes of action during the next month.

Melons: Continue to scout melons for aphids, cucumber beetles, spider mites and rind-feeding lepidopteran worms (yellow striped armyworm, corn earworm, beet armyworm). Beet armyworm and corn earworm are completely or partially resistant to pyrethroids. Any fields that were treated with broad-spectrum insecticides, such as pyrethroids, should be checked since they can severely reduce these natural enemies causing spider mite outbreaks.  If you see large aphid populations, look for beneficial insect activity.  If numerous lady beetle, syprhid maggot and lacewing larvae are present, wait and check a few days later as these natural enemies can greatly reduce aphid population. The cool night will also slow them down aphid population growth.  These infestations can be spotty/localized so treatment might not be across the whole field.

 

Tomato and Blossom End Rot

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By Jerry Brust, IPM Vegetable Specialist, University of Maryland

This is just a reminder with the usual summer weather we have had lately with stretches of very high temperatures and the occasional very heavy down pour we have had over the last few weeks blossom end rot can become a real problem in tomatoes. Sunny days will suck water through a plant quickly and the downpours will disrupt calcium movement through the plant. The key is to try and maintain consistent soil moisture while the fruit is developing. Easier said than done I know, but soil moisture levels need to be monitored as best as they can. When you see something like figure 1, with all the tomatoes on a cluster with blossom end rot you know the soil moisture fluctuated greatly over a fairly long period of time. Applying some foliar calcium sprays may help, but the applications can’t overcome poor soil moisture management.

Cluster of green tomatoes with blossom end rot ( browning at the base).
Fig. 1 All the tomatoes on this one cluster have blossom end rot—indicating poor soil moisture management. Photo By J. Brust. 

Possible Changes to Atrazine Use

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By Kurt M. Vollmer, UME Extension Weed Management Specialist

The EPA is proposing several changes to its interim registration review decision for atrazine. The primary issue is the aquatic ecosystem level of concern (CE-LOC). The EPA had previously set this level at 15 ppb, but this was challenged in the Ninth Circuit Court of Appeals. Currently the EPA is proposing a much lower CE-LOC level of 3.4 ppb. This proposed level will have significant impacts on growers’ ability to use atrazine and other triazine products. Labels will also likely include new language to help mitigate the risk to aquatic plant communities. These include:

  • restricting atrazine applications when soils are saturated,
  • restricting atrazine applications during rain or storm events,
  • prohibiting aerial applications,
  • and reducing the annual atrazine application rate from 2.5 lbs. to 2 lbs. per acre annually.

Additional information can be found here: https://list.mg2.mlgnserv.com/track/click?u=df0ec74ed0bf23e091847f07c1d2c483&id=c31eec13d8967c36&e=d300d03f14fec2b3https://list.mg2.mlgnserv.com/track/click?u=df0ec74ed0bf23e091847f07c1d2c483&id=c31eec13d8967c36&e=d300d03f14fec2b3. The EPA is currently seeking public comments about the proposed decision (https://www.epa.gov/dockets/commenting-epa-dockets).

In addition the USDA Office of Pest Management Policy is conducting a related survey on atrazine usage practices for farmers involved in corn and sorghum production over the last three years (https://usdaopmp.gov1.qualtrics.com/jfe/form/SV_agW8JjsVXqR4jjg). 

New Risk Management Tools Online Training

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This summer, the University of Maryland (UMD) is partnering with the Maryland Department of Agriculture (MDA) and USDA to create a four-module online training course Maryland Farming Success.

The online training course is separated into four modules designed around preparing farmers for success by providing information about available USDA programs and creating the ability for participants to have a successful business plan, including – mission and goals, enterprise budgeting, risk management, and legal risk management.

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