Rutgers University | New Jersey Agricultural Experiment Station | Pesticide User Responsibility

Archives for April 2020

April 6, 2020

Controlling Septoria Leaf Spot and Bacterial Leaf Blight in Parsley

Septoria leaf spot (SLS) in Parsley can cause significant losses in fields where it has become established. Like other Septoria’s, the leaf spots produced on parsley look much like the leaf spots produced on tomatoes and other crops. Septoria leaf spot overwinters from year to year on infected debris so long crop rotations of 2 or more years are important to help reduce disease pressure. During the season, SLS will spread rapidly with each subsequent rainfall and/or overhead irrigation event. Therefore, early detection and preventative fungicide applications are key to successfully controlling SLS. There have been a few new fungicides labeled for SLS control in the past few years.

Parsley SLS

Septoria leaf spot of Parsley

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Filed Under: Vegetable Crops Tagged With: , ,
April 4, 2020

Vegetable Disease Update – 4/4/20

Warmer days and cool nights, along with cool soils and the regular wet weather has made conditions ideal for disease development in some spring crops. Growers should consider applying preventative fungicide applications for early-season diseases, particularly root rots, either in the transplant water or shortly after transplanting or seeding to help mitigate potential issues. All fields should be scouted on a regular basis. White rust and anthracnose were reported on spinach this week, so leaf spot pathogens are already active.

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Filed Under: Vegetable Crops Tagged With: , , , ,
April 4, 2020

Controlling white mold in spring crops

White mold, or lettuce drop, caused by Sclerotinia sclerotiorum, can cause serious losses in lettuce and other susceptible crops if left uncontrolled. Disease development is favored by wet, humid conditions (especially in high tunnels and fields) with known histories of the disease.

WhiteMold

White mold on lettuce. Notice the white fungal growth and black sclerotia developing on the base of the stem. The sclorotia can survive in the soil for up to 10 years.

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Filed Under: Vegetable Crops Tagged With:
April 4, 2020

Damping-off: Identifying and Controlling Early-Season Damping-off Pathogens

It is extremely important to know which pathogen is causing damping-off problems and which fungicide to properly apply. The key to controlling damping-off is being proactive instead of reactive. Always refer to the fungicide label for crop use, pathogens controlled, and application rates.

Damping-off is caused by a number of important vegetable pathogens and is very common during the spring. Damping-off can kill seedlings before they break the soil line (pre-emergent damping-off) or kill seedlings soon after they emerge (post-emergent damping-off). Common pathogens that cause damping-off include Pythium, Phytophthora, Rhizoctonia and Fusarium spp.

Control of damping-off depends on a number of factors. First, is recognizing the conditions which may be leading to the problem (i.e., weather/greenhouse growing conditions) and second, identifying the pathogen causing the problem.

Conditions Favoring Damping-off

Although all four pathogens are associated with damping-off, the conditions which favor their development are very different. In general, Phytophthora and Pythium are more likely to cause damping-off in cool, wet or overwatered soils that aren’t allowed to dry out due to cloudy weather or cooler temperatures. Conversely, Rhizoctonia and Fusarium are more likely to cause damping-off under warmer, drier conditions especially if plug trays are kept on the dry side to help reduce transplant growth. [Read more…]

Filed Under: Vegetable Crops
April 4, 2020

Organic Transplant Production: Suppressing Soil-borne Pathogens – A reminder

Pathogens such as Fusarium, Pythium, Phytophthora, Thielaviopsis and Rhizoctonia that cause pre- and post-emergent damping-off can cause serious problems in organic (and conventional) transplant production. The key to controlling and/or suppressing damping-off pathogens with biological controls is keeping the biological populations high and continually present on root surfaces of the host, and by following good cultural practices. [Read more…]

Filed Under: Vegetable Crops Tagged With: , ,
April 4, 2020

Controlling Spring Diseases in Asparagus

Asparagus season is just around the corner and now is a good time to review important diseases.

Wet soil conditions are ideal for Phytophthora and Pythium development. To help reduce potential losses, especially in fields with low spots or fields that are poorly drained soils, or more importantly, in fields with a history of either disease apply Orondis Gold (oxathiapiprolin + mefenoxam (FRAC groups 49 + 4) at 4.8 to 9.6 fl oz/A, Ridomil Gold 4SL (mefenoxam, 4) at 1.0 pt/A, or Ultra Flourish 2E/A (mefenoxam, 4) at 2.0 pt/A, or MetaStar 2E (metalaxyl, 4) at 2.0 qt/A over beds just before first harvest. For new plantings, apply the same after planting or after crown covering. Do not apply Orondis Gold, Ridomil, Ultra Flourish, or MetaStar one day prior to harvest or illegal residues may result. [Read more…]

Filed Under: Vegetable Crops Tagged With: