Archives May 2018

Darksided Cutworm
Euxoa messoria
Week 2 (May 14) Darksided cutworm

Identification
adults: Forewings grayish, each with an oval and a kidney-shaped paler spot with darker margins among irregular dark lines. Wingspan of about 35 mm. mature larvae: Hairless, up to 37 mm in length. Grayish in color with a prominent white stripe along each side just above the legs; upper surface with a reddish background color. Head is orange-brown with darker spots.

Distribution
Native to North America. Distributed from Atlantic to Pacific coasts, north from the southern USA into southern Canada.Lifecycle
Females lay up to 1000 eggs in soil or under debris in cultivated fields. Mature larvae enter a non-feeding pre-pupal stage for about 30 days before pupating. One generation per year.

Hosts
Broad range of herbaceous and woody hosts including vegetables, cereals, canola, corn, tobacco, flax, sunflower, vine, berry and tree fruits.

Feeding damage
above-ground (climbing) cutworm: Larvae feed at night on the leaves and stems of young plants causing defoliation
and death. Areas of bare soil increasing in size soon after crop emergence may indicate cutworm feeding damage.

Monitoring/Control
Inspect bare patches and surrounding margins for larvae, which hide at the base of plants during the day. Count the number of larvae in a 50 cm x 50 cm area of the crop; multiply by four to estimate the number of larvae per m2. Repeat this process 5 to 10 times at 50 m intervals.

Insecticide treatments may be warranted if economic thresholds are exceeded, but take steps to minimize effects on natural enemies; see
General Control Options (p. 26).

Economic threshold
cereal and oilseed crops: 5-6 larvae/ m2 (Phillip 2015).
peas: 2-3 larvae/m2.
dry beans and soybeans: 1 small (<2.5 cm long) larva/m of row or 20% of plants cut.

Notes
Larvae are similar in color to redbacked cutworm. The most destructive pest of tobacco throughout most tobacco growing regions of Canada (Cheng 1984). Can be particularly damaging to buds of trees and shrubs (Walkden 1950).

For more photos and to view the full pdf click here–> Week 2 Darksided cutworm

Cutworm Pests of Crops on the Canadian Prairies: Identification and Management Field Guide

Prairie Pest Monitoring Network Blog

Water intake for dry beef cows is around 1-1½ gals./100 lbs. of body weight and this estimate can double for cows nursing calves.

Summer has arrived but there are many areas that don’t get enough runoff water to adequately fill the stock ponds, forcing producers to move cattle looking for forage and water. When drought causes a great reduction in surface water available in farm ponds, the issue of water quality becomes nearly as important as quantity of water available.

Water is the one most important nutrient required by livestock. Decreased intake can adversely affect health, reproduction and growth. Excessive salinity (salt) in livestock drinking water can upset the animals’ water balance and cause death. Unsafe levels of salt and toxins depend on the age of the animal, its stage of production and the amount of water consumed each day.

Water consumption is dependent on many factors. Water intake for dry beef cows is around 1-1½ gals./100 lbs. of body weight and this estimate can double for cows nursing calves.

Oklahoma has many potential sources for run-off pond water contamination.

•  Soil minerals and salt leaching from the ground.
•  Oilfield drilling sites and saltwater disposal wells.
•  Agriculture application of nitrate and sulfate fertilizer.
•  Animal manure and human waste control systems.

Suggested uses of livestock water containing different levels of contaminants are listed below: (remember 1ppm = 1mg/liter of water)

Nitrates: 100 ppm or less should not harm livestock.100-300 ppm should not harm livestock by itself, but beware of additive effects when animals are exposed to or grazing foodstuffs containing increased levels of nitrates (sudan, haygrazer and johnsongrass).
Sulfates: Water levels of 2,000-2,500 ppm and sulfate levels in foodstuffs allowing the animal to attain a level of 4,000 ppm or greater; can be associated with a neurological disease in cattle causing blindness.
Total Salts:

•  Less than 1,000 ppm: These waters have a relatively low level of salinity and should present no serious burden to livestock.
•  1,000-2,999 ppm: These waters should be satisfactory for all classes of livestock. They may cause temporary and mild diarrhea in livestock not accustomed to them, but should not affect their health or performance.
•  3,000-4,999 ppm: These waters should be satisfactory for livestock, although they might very possibly cause mild diarrhea or be refused at first by animals not accustomed to them.
•  5,000-6,999 ppm: These waters can be used with reasonable safety for dairy and beef cattle, sheep, pigs, and horses. It may be well to avoid the use of waters approaching the higher levels for pregnant and lactating animals.
•  7,000-10,000 ppm: These waters are unfit for pigs. Considerable risk may exist in using them for pregnant and lactating livestock. In general, their use should be avoided, although older animals may subsist on them for long periods of time under conditions of maintenance and low stress.
•  Greater than 10,000 ppm: The risk of these high salinity waters are so great that they cannot be recommended for use under any conditions.

A routine water analysis performed at a lab with the help of your county Extension educator or local practicing veterinarian can be very helpful and cost very little. This would take all the guesswork out of trying to decide which animals would be safe to drink the water and which pastures might be able to be grazed.

As ponds start drying up, the concentration of salt and toxic ions begins to increase in them. Do the young calves in the group have a mild diarrhea due to salty water or coccidiosis? Do the distillers by-product feeds (which can be high in sulfur) have the potential to cause blindness in creep fed to my calves? Are pregnant cows at risk while grazing sudan forage and drinking water possibly containing nitrates? All these questions might be answered by a simple, routine livestock water analysis.

Rules of Thumb for livestock Drinking Water Quality Article link