Archives for October 2013

October 25, 2013 Dave Schmitt

Integrate Sanitation Into Your Apple Scab Control Program

Apple Scab Control with Urea.
Video link: http://youtu.be/8g0WyVi68GM

This past season we saw elevated levels of apple scab in southern counties. Our IPM scouts found low levels of scab present in orchards where scab had not been detected for many years, even though these orchards had been carefully sprayed using effective materials. Most likely what we are witnessing is the result of an increasing pattern of wet seasons with periods of extreme rainfall and not resistance to DMI fungicides, although that is an area of great concern and cannot be ruled out. Regardless of the cause, high inoculum in the orchard will eventually lead to control failures with materials such as the DMI’s and other chemistries prone to resistance.

At any rate growers that had scab this year should integrate sanitation practices into their scab control program. The recommended sanitation program involves either: fall or spring applications of Urea; flail mowing fallen leaves: or preferably both.

Dr. Dan Cooley and Jon Clements at UMass have uploaded a short video explaining this approach.

Filed Under: Tree Fruit

October 21, 2013 Andy Wyenandt

Late Blight Confirmed on Organic Tomato in South Jersey

Late blight was confirmed in an organic tomato field late last week south of Bridgeton, New Jersey. As a note, growers who are still picking tomatoes should continue to scout up until the final pick and destroy field as soon as possible once harvesting is finished either by applying gramoxone or discing under plant material. Growers with late blight issues this growing season should be especially diligent. The threat of late blight in our area will remain up until the first frost. Late blight has the potential to overwinter in our area on infested potatoes left in cull piles or unharvested tubers left in the field.

Filed Under: Organic Production Tagged With: Late blight, tomato

October 9, 2013 Kris Holmstrom and Joe Ingerson-Mahar

Veg IPM Update: Week Ending 10/09/13

Vegetable IPM Report 10-09-13 – Click to View | Download | Print

Current Week’s Pest Maps – Available Maps for the week are highlighted

European Corn Borer Map
Corn Earworm Blacklight Map
Corn Earworm Pheromone Map
Brown Marmorated Stinkbug Map
Vegetable IPM Pest Map Archive

Filed Under: Vegetable Crops

October 4, 2013 Andy Wyenandt

Angular Leaf Spot in Fall Transplanted-Strawberries

There have been a few reports of angular leaf spot (ALS) caused by the bacterium, Xanthomonas fragariae, in strawberry in the northern part of New Jersey. Often considered a minor pathogen, ALS can cause serious leaf and calyx infections ruining the marketability of fruit if left uncontrolled. Like all bacterium, the pathogen will infect leaves and the calyx through natural openings or wounds.

Fig. 1. Water-soaked lesions caused by angular leaf spot on infect strawberry leaf. Photo by P. Nitzsche

Infections can often start in production operations and come in on infected bare root transplants or cuttings. Symptoms on leaves include initial small, irregular water-soaked lesions (Figure 1).

Fig. 2. Reddish-brown lesions on infected strawberry leaf caused by angular leaf spot. Note the translucent spots when held up to light. Photo by P. Nitzsche

As disease progresses lesions will enlarge and coalesce forming reddish-brown spots on leaf surfaces which later become necrotic and translucent (Fig. 2). Holding infected leaves up to the light will reveal this diagnostic feature.

Importantly, in severe outbreaks in the spring, the bacterium can spread to fruit causing the calyx to turn brown and dry out ruining the marketability of infected fruit (Figs. 3 & 4).

Fig. 3. Angular leaf spot infections on calyx of infected strawberry fruit. Photo by P. Nitzsche

Fig 4. Strawberry fruit infected with Angular leaf spot. Note the brown, dried up calyx.

The pathogen is easily spread via overhead irrigation and during rain and can be moved around the field during harvest. The bacterium may overwinter on infected plant debris buried in the soil for up to one year. The best method for controlling angular leaf spot is to buy clean transplant material. Conventional or organic copper-based products can help suppress the development of ALS, and should be applied at a low rate to avoid phytotoxicity in leaves. Weekly, preventative applications of 0.3 lb fixed copper have been shown to be effective in reducing ALS if applied early enough when disease pressure was still low.

Filed Under: Vegetable Crops Tagged With: angular leaf spot, strawberry

October 4, 2013 Steven K. Rettke

Cool Season Mites Wax as the Warm Season Mites Wane

In the New Jersey region, the late weeks of September & early weeks of October are transition periods for warm season & cool season spider mite species found in landscapes & nurseries. The spruce spider mite & the southern red spider mite are the most common cool season species & they are now “waking-up” from their summer inactive period. Alternatively, the warm season two-spotted spider mite may have stopped feeding or will soon cease. They are rapidly declining & preparing to depart the leaves of their host plants if they have not already done so.

Two-spotted spider mites that produced these stippling symptoms on burning bush this summer are now entering dormancy with the arrival of autumn
(Photo: Steven K. Rettke of RCE)

Spruce spider mites that were previously in a summer dormancy are now resuming activity again on this Frasier-fir as the autumn season arrives (Salem County Nursery) (Photo: Steven K. Rettke of RCE)

[Read more…]

Filed Under: Landscape, Nursery, & Turf

October 2, 2013 Administrator

“Rain Shadows”

By Jim Murphy

Many people are aware that tree root competition is part of the challenge of maintaining turf within the drip line of trees. But the canopy of trees also contributes to the challenge by capturing and retaining much, and in some cases all, of a rain.

Rain shadows have been evident for some time now but the damage from the soil dryness has reached moderate to severe levels over the last couple weeks. Many of the lighter rainfalls over the last month haven’t wet the grass let alone the soil under large trees at Hort Farm No. 2 in North Brunswick.

The cumulative effects of a “rain shadow” and tree root competition lead to drought stress under trees.

Filed Under: Turf