INTRODUCTION
Pumpkin acreage in Kentucky has increased recently. Also, more growers are benefiting from double cropping their fields by planting pumpkins after winter wheat. They harvest two crops in one season, and they also benefit from the wheat stubble left after harvest. It is a natural weed control barrier. This is becoming popular with growers. Some are sacrificing a fall-planted rye or wheat crop with an herbicide kill, pushing the dead straw down, and no-till planting pumpkins on the heavy straw stubble. One advantage is that expensive, selective herbicides have to be used only in the planting strip instead of the whole field.

MATERIALS AND METHODS
In order to evaluate this system, an experiment was started in fall 2005 with the drill seeding of winter wheat at about 90 lb/A. Wheat was burned down with Gramoxone on 10 June 2006, which was later rolled down to provide a thick cover.

Herbicides were applied using a CO₂-pressurized backpack sprayer with a 4-nozzle boom calibrated to spray a 5 ft band at 30 psi and a 3 mph walking speed. The 8002-nozzles were set at 17 inches above ground to obtain good spray overlap and complete weed coverage.

Plots were 10 ft x 35 ft long. The experimental design consisted of a randomized complete block with three replications. Each plot was sprayed with two passes of the boom to cover the 10 ft plot width.

Preemergence herbicide treatments were applied on 19 June five days after seeding pumpkins using a no-till tobacco transplanter to cut the mulch and disc the planting strip. Postemergence herbicide treatments were applied on 11 July. Two varieties of small-fruited pumpkins were planted in each plot; Cotton Candy (white) and Hybrid Pam (orange).

Visual weed control ratings were collected at various dates. The scale used in these ratings were on a 1-10 scale, with 1 = no control and 10 = complete kill or no weeds present. A rating of 7 (70-75% control) or more is considered a commercially acceptable value.

RESULTS
About two weeks after preemergence (PRE) application, weeds were completely controlled by all treatments, except Sandea at 0.047 lb ai, with only 60% control. Weeds in this treatment consisted of grasses, which is expected since Sandea has no grass control effectiveness. Significant visual injury to the two pumpkin cultivars was observed with the following treatments: Outlook high rate (1.32 lb ai), Spartan high rate (0.38 lb ai), Prowl + Sandea and Sandea 0.047 lb ai.

Pumpkin stand and vigor were comparable in the control plots and in the plots treated with the labeled herbicide Strategy. Similar observation were seen with the non-labeled herbicide Outlook at the 0.66 lb ai rate.

In table 2, visual injury ratings for postemergence (POST) herbicides apply to treatments 7 and 8 only. The other visual injury ratings are for the PRE treatments and would be equivalent to ratings taken 36 days after PRE application. At 36 days after PRE application (trts 2-6, 9-10), crop injury was still observed for only Spartan at the high rate (0.38 lb ai). All other treatments that showed injury at 14 DAT, namely 4, 9 and 10, do not show any further injury at 36 DAT and appear to be safe on both cultivars.

At 14 days after POST application, treatments 7 and 8 showed significant injury ratings on the Cotton Candy pumpkin, but not statistically different from the control for Hybrid Pam. The addition of Chateau to V-10142 significantly improved the overall weed control effectiveness.

At harvest, only Hybrid Pam was harvested. All Cotton Candy fruit had rotted due to a severe powdery mildew infection. Table 3 shows data for Hybrid Pam. Of the treatments that showed significant injury at 17 DAT (namely, treatments 4, 6, 9, 10), only treatments 6, 9, and 10 had effect on yields, even though visual injury symptoms had disappeared by 36 DAT (see table 2 above). Outlook 1.32 lb ai had no residual effect, didn’t affect yields at harvest, and was similar to the rate of 0.66 lb ai. Yields of Outlook plots were similar to the Strategy plots. Significant yield reduction was observed with treatments 6-10 (table 3), both in terms of number of pumpkins per plot and total weight per plot.

At this stage, it appears that V-10142 is not safe for use on pumpkins as a directed postemergence herbicide. Neither are Sandea alone or in combination with Prowl, nor Spartan at the high rate of 0.38 lb ai. Spartan at low rate of 0.19 lb ai and Outlook appear to be safe for use as a preemergence herbicide in no-till pumpkin.