NDSU Crop and Pest Report

FROM AROUND THE STATE


ISSUE 7   June 17, 2004

North-Central ND

PEST UPDATE

Early Hatch of Grasshoppers Slow and Low with Cool Wet Weather!

Continue to Monitor the Late Hatching Grasshoppers for Movement into Agricultural Crops.

The majority of grasshoppers that hatched early during the cool, rainy periods of May and early June were killed or drowned in the heavy rains. Or, they may have succumbed to fungal diseases. In the north central region, the hatch is estimated to be about <50% completed. Grasshoppers should start emerging again when temperatures warm up. A few reports of damaging numbers of grasshoppers have just been reported in some "hot" spots with sandy soils in north central region this week. So, continue monitoring the later hatching grasshoppers for their movements into field edges of agricultural crops.

Canola Insect Pest Update:

Crucifer flea beetle populations lower than previous years in North Central Region of ND – so far!

Although high populations of crucifer flea beetles were detected last summer in swathed fields in the north central region of ND, the overall flea beetle pressures have been lower than expected on spring canola fields. Possible reasons for the lower pressures are:

  1. Warm temperatures in early spring encouraged flea beetles to come out of their overwintering (hibernating) state. This was followed by an unseasonably cool, wet conditions causing some mortality of emerging flea beetles
  2. Unfavorable temperatures (below 60ºF), rain and high winds limited feeding and movements into spring planted canola fields during critical times for flea beetle survival
  3. Diseases and other natural factors helped reduce flea beetle populations

In other areas of the state like northeast and south central regions, flea beetle populations have been higher. However, the overall weather conditions have not been favorable for flea beetle feeding and movement reducing the risk to the canola crop.

So far, most of the spring canola also appears to have escaped the need for a foliar insecticide spray on top of the seed treatments. Continue to monitor late season flea beetle activity in canola fields into early June, especially on warm and calm days. Canola plants in the 6-8 leaf stage should be able to out grow flea beetle feeding injury. Remember, to check the growing point in the center of the canola plant and be sure the flea beetles are not feeding on it!

Canola producers in Manitoba, Canada are experiencing heavy flea beetle feeding activity this year. "Flea beetle feeding was intense in many canola fields early last week, when the weather was warmer, and foliar sprays were applied in some fields. Some of the fields being treated with foliar sprays had also used insecticide treated canola seed. In many early seeded canola fields the flea beetle protection from the seed treatment will no longer be effective."

(Source: J. Gavloski, Manitoba Insect and Disease Update, June 14, 2004).

Diamondback Moth Trap Catches are low!

Trap reports of diamondback moth, a migratory insect pest of canola, have been very low for the past week. Here’s a summary of the number of moths captured per week from some of the trap sites:

McKenzie County, Watford City = 26 (Dale Naze); Divide County, Crosby = 10 (Keith Brown); Renville County, Mohall = 6 (Lorilie Atkinson); Bottineau County: Bottineau = 18, Kramer = 23 (Tim Semler); Ward County: Minot = 11 (Lorilie Atkinson); and Southwest ND: New England = 51, Dickinson =11 (Roger Ashley).

So far, the risk of diamondback moth is low to canola. To have damaging levels, diamondback moth must arrive early in mid to late May in high numbers. The second generation that develops during late June to early July is usually the most damaging to the flowering canola crop. The cool, wet, windy weather conditions have not been conducive to adult activities like female egg laying either. Although no larvae have been found, heavy rains can drown diamondback moth larvae and reduce populations in half. Rainfall also promotes natural diseases like Entomophthorales fungi, which helps control diamondback moth populations.

Sunflower Insect Pests
Sunflower Beetle is emerging and laying eggs!

Scout sunflower fields for the sunflower beetle. Some activity has been observed. Economic threshold is 1_2 adult sunflower beetles per seedling. Foliar insecticides registered in sunflower can usually be tanked mixed with herbicides. But, please read the label and follow the mixing directions.

Janet J. Knodel
Area Extension Specialist Crop Protection
North Central Research and Extension Center
Minot, ND

 

Northeast ND

Areas in Rolette, Benson and Towner counties received up to two inches of rain last week while the rest of the region received from a quarter of an inch to one inch of rain. Planting will conclude this week as some growers are finishing planting Sunflower, dry bean and some flax and small grain. Up to 25% of the crop acreage is estimated not planted or flooded in Rolette and Towner counties. Other counties are estimated to have between 5 and 15% not plant and flooded. Localized areas have more severe damage.

Cool season crops continue to benefit from the cool temperatures. Warm season crops are growing slowly. Soybeans are emerging with minimal problems. Sunflower and dry beans are starting to emerge to two leaf stage. Wildoat and broadleaf weed spraying is ongoing although difficult due to extreme soil wetness. Flea beetles have not caused any wide spread problems in canola. Winter wheat is in the boot stage. Infections of tan spot in wheat and net blotch in barley are common. Crop yellowing is common.

Terry Gregoire
Area Extension Agronomist
Devils Lake Area Office
tgregoir@ndsuext.nodak.edu

 

Southwest ND

Last week saw the first significant rainfall since April 17 (>0.25 inches) for many southwest areas but the region remains well below normal. Many hay fields will produce less than half of the forage they did a year ago and in some cases so little forage will be produced that haying will not be possible. Alfalfa weevils have been reported and producers are treating when populations warrant.

In severe drought affected fields, crops are short. In other areas where stored soil moisture more abundant and rainfall more plentiful, crops are doing well. Winter wheat is flowering and early seeded spring wheat is in the boot. Corn has emerged but cool weather is restricting growth rates.

Roger Ashley
Area Extension Agronomist
Dickinson Research Ext. Center
rashley@ndsuext.nodak.edu

 

South-Central ND

Moisture extremes are present in the region, with Burleigh and Emmons counties being dry while the rest of the region generally has adequate to excessive soil moisture. During the past week (June 9 to 15), the south-central region’s rainfall ranged from 0.29 inches at Fingal to 2.37 inches at Edgeley and Harvey as recorded at NDAWN (North Dakota Agricultural Weather Network) sites. Most of the region received 1 to 2 inches of rain.

The region’s crop planting essentially is complete, except for warm-season annual forages. Winter wheat generally is near or at heading. Spring wheat and barley stages range from tillering to boot, with the majority of the acreage jointing. Yield potential of small grain continues to be generally excellent (except in southwest counties) due to cool weather conditions and ample soil moisture. Sunshine and warmer weather is needed for corn, beans and sunflower. Corn growth is finally starting to accelerate. Soybean, dry bean, and sunflower emergence are variable and stands are still being established due to factors including cool, wet and crusted soils. Pests also sporadically have reduced crop stands including wireworm, cutworm, seed corn maggot, geese and gophers.

POST herbicide spraying in small grain is nearing completion, while corn and soybean spraying is in progress. Pesticide application continues to be a challenging task due to rain, water-saturated soils, and wind. Common leaf diseases include tan spot in wheat and net blotch in barley. Also, leaf rust has been detected in tillering spring wheat in Kidder County and probably can be found in other southern counties.

Greg Endres
Area Extension Specialist/Cropping Systems
NDSU Carrington Research Extension Center
Gregory.Endres@ndsu.nodak.edu


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