Weed of the Week: Wild Buckwheat

Common Name: Wild Buckwheat

Latin Name: Polygonum convolvulus

Wild buckwheat is an annual weed that can be found in crop fields, hay fields and waste areas. At the seedling stage, this weed is easily identified by its cotyledons which are linear and positions 120 degrees from each other. Its true leaves are arrow-shaped with pointy tips. Wild buckwheat has a tap root and a twining growth habit. The vines become entangled with the crop causing lodging and making harvest difficult.

When mature, small flowers are produced, although wild buckwheat flowers lack petals, there are five whitish-green sepals that tightly enclose a single seed. Each seed is dull, dark brown to black and triangular in cross section.

From Amanda Homans, Agronomist with McRae Holdings.

Your Report card on Germination

Most crops are in the ground and a large portion of them are already out. Now, it’s time to assess how you did. Walk your fields and dig in a few places to check seeding depth. You cannot do much about poor seeding depths or seed/fertilizer separation problems now, but while things are still fresh in your mind, you may be able to remember why you had issues and make the necessary notes or changes so it does not happen again next year.

Seeding depth is the biggest issue I have seen this year again. Like most years seeding is started and sometimes even completed in cool wet soils. Under these conditions plants do not grow very quickly and they use more energy thus making seeding depth even more important. Planting depth should be determined by the length of the coleoptile.

Speed is another factor that contributes to poor emergence. If, for example, you were seeding too fast and there was some mixing of the seed row and banded row, germination could be effected because of the salt index in and near the seed. Speed can also bury seed under excess soil as it does not roll back over the shoe as it is designed to do. Exposed seed can also be a speed/ shoe design issue. Find an optional speed and stick to it despite the rain clouds over head.

Soil texture is another major reason for seed depth variations. When you move from one field to another soil texture likely also changes due to the soil characteristics. Your seeding equipment will likely sink deeper in a sandier soil than a clay soil so adjustments need to be made. Did you make them?

No matter how unlimited or limited our budget is after seeding we cannot change our seeding depth or speed. Do it right the first time. If you were too busy to check every field when you were seed now is the time to face the piper and check to see if you passed or failed.

Terry Bonertz, CCA

 

Pea Leaf Weevil- Check your Fields

A Pea Leaf Weevils is an insect that feeds on the roots (larvae) and leaves (adult) of peas, fababeans and dry beans. In southern Alberta peas are the major crop at risk for damage. Most of the damage occurs from the larvae feeding on the nitrogen-fixing nodules, adults chewing on the leaves and growing points can also cause extreme damage.

The adult is slender, grayish-brown and about 5mm long. Pea Leaf Weevils can be distinguished by the three light-colored stripes extending lengthwise down its body. The larvae are “C” shaped, light milky white in color with a dark brown head, legless, cylindrical, soft and fleshy and 3.5-5.5mm in length.

Under Alberta conditions, the Pea Leaf Weevils produce one generation per year. Adult Pea Leaf Weevils overwinter in alfalfa. In the spring, Pea Leaf Weevils moves either by flying or walking short distances. The females lay 1000-1500 eggs in the soil near or on developing plants in May through June. Upon hatching the larvae move to the nodules where they feed.

Foliar application of insecticide is recommended if there are 1-2 bite marks per plant. This being said, please scout your pea fields or give us a call and we can come at check them for you.

From Amanda Homans, Agronomist with McRae Holdings.

Weed of the Week: Wild Oats

Common Name: Wild Oats

Latin Name: Grass Poaceae

Wild Oats are an annual weed that can be found in crop land, hay fields and irrigation. Unlike grasses, wild oats have a counter clockwise twist to the leaves. Other easily distinguishable features include a tall, membranous lingual, and an easy to recognize seed when uprooted.

When mature, the inflorescence (flowering part of the plant) is very large and often seen waving above the crop canopy. The seeds vary color from beige to black, and they are usually hairy, especially around the base. All wild oat seeds have a large ‘sucker mouth’ and bent awn.

From Amanda Homans, Agronomist with McRae Holdings.