Sweet Corn

By this time last year, we had already begun catching European corn borer (ECB) adults, as well as a few corn earworm (CEW) adults. Due to much cooler conditions this season, blacklight trap catches have very few insects of any type. As a result, there will be no maps published in this IPM Update. In general, sweet corn is well behind recent seasons in terms of development. As ECB numbers develop, their activity will be reported here.

Cole Crops

In many locations, imported cabbageworm butterflies (ICW) are active. These butterflies were seen laying eggs on kale in Hunterdon County this week. Egg deposition is undoubtedly occurring all over the state, during warm periods. Be sure to check the youngest portions of plants, as this is often where the ICW larvae go to feed. Feeding can damage the growing point of plants, if it is not detected in time. Check 5 consecutive plants each in 10 random locations throughout the field. Consider treating if caterpillars are found on 10% or more plants that are in the 0-9 true leaf stage. From 9-leaf to the early head stage (in broccoli, cauliflower and cabbage) infestations up to 20% may be tolerated. Once heads begin to form, a 5% threshold should be observed to protect the marketable portion of the plant. For leafy greens such as collards and kale, 10% plants infested is the threshold throughout.

Crucifer flea beetle is active on many plantings, particularly when conditions are warm. When scouting cole crops for caterpillar pests, check for the presence of flea beetles. Consider treating if flea beetles are present on 50% or more plants, and feeding injury is evident on the plants. Be sure to monitor newly emerged or transplanted fields for the presence of this pest. In general, plants like arugula and mustard (those with a “hotter” flavor) are more favorable to flea beetles.

Parsley

Septoria Leaf Spot – has been found in east Vineland this past week.

Leaf spots caused by Septoria blight are easily distinguished by small, angular to round leaf spots with grayish-brown centers with a definitive dark, brown margin. Numerous black fruiting bodies develop in the center of lesions (see VDOW). Septoria blight is spread by wind-driven rain and overhead irrigation.

Rotate applications of Quadris (azoxystrobin, 11) at 6.0 to 15.5 fl oz 2.08SC/A or Cabrio (pyraclostrobin, 11) at 12.0 to 16.0 20WG/A with Tilt (propiconazole, 3) at 3.0 to 4.0 fl oz. 3.6F/A every 7 days. A fixed copper at labeled rates can also be included if bacterial leaf spot is an issue.

Bacterial leaf spot (Pseudomonas syringae) of parsley can also show up at the same time as Septoria blight.  Leaf spots caused by Bacterial blight appear as small brown to black spots on the leaves.  The pathogen can be soil or seed borne and develops during cool, moist weather.  The disease spreads during cool, rainy weather or with overhead irrigation; and is exacerbated by high plant density.  The same control measures listed for Septoria will assist in preventing the spread of Bacterial leaf spot as long as the fixed copper is included with azoxystrobin and the fungicides are applied preventatively.  If Oxidate is used, follow the label carefully. [Read more…]

Rutgers Cooperative Extension IPM personnel are currently deploying blacklight trap and insect pheromone trap networks throughout the state. Sampling will commence within one week, and insect data will be published in the Plant and Pest Advisory Online and on the Pest Map Archive as soon as target pests begin to appear. [Read more…]

Leaf spots were reported in spinach and other greens this past week. Growers should remain diligent and scout on a regular basis. With the dry weather expected over the next week, any use of overhead irrigation will help spread potential disease. Growers should apply preventative fungicides in advance of any disease developement or use of overhead irrigation.

Rhizoctonia was found in strawberry this past week. Rhizoctonia tends to show up during dryer weather periods usually on stressed plants. In general, the longer transplants sit in the ground without getting established and putting on any new growth the more susceptible they become to pathogens such as Rhizoctonia. Abound (azoxystrobin, 11) at 6.0 to 15.5 fl oz as a foliar application, or 0.40 to 0.80 fl oz/1000 ft row has a broad label for Rhizoctonia suppression across many crops. Abound will also help control pathogens such as anthracnose fruit rot, leaf spots, and powdery mildew in strawberry.