Grainews

Page 1

Volume 42, Number 11  |  MAY 17, 2016

$4.25

PRACTICAL PRODUCTION TIPS FOR THE PRAIRIE FARMER

www.grainews.ca

Be ready to scout your fields. This pest is headed north

Crescent-shaped notches on pea leaves are evidence of the presence of pea leaf weevils.

By Marianne Stamm

T

here’s a new pest heading north in Alberta and it’s moving fast. Although a regular in southern Alberta and southern Saskatchewan, the pea leaf weevil has now been sighted as far north as Athabasca, Alberta. “There’s been a real range expansion,” says Scott Meers, insect management specialist with Alberta Agriculture. “It’s a concerning issue for the Highway 2 corridor in Alberta. We’ve seen some very significant numbers, especially in the Red Deer and Lacombe area.” As damage from the pea leaf weevil can be up to 20 percent of crop yield, it’s worth taking note of this insect. According to Meers, the best chemical control practice is insecticide seed treatment so farmers would be wise to inform themselves now of the risk to their fields.

The life of the pea weevil The adult pea leaf weevil emerges from its winter habitat of ditches,

Publications Mail Agreement Number 40069240

shelterbelts or perennial legume fields in late April/early May. It begins feeding on available leguminous greens and then moves into pea or fava bean fields to reproduce. The pea leaf weevil is a five millimetre, slender, greyish-brown insect with a short snout. Three light-coloured stripes run along its abdomen. It’s not an easy insect to spot, as it drops to the ground on approach, where it’s hard to see. Evidence of its presence comes from crescent-shaped notches on pea leaves. It’s not the feeding of the adult pea leaf weevils that causes enough damage for economic concern. The problem is the larvae that develop and feed on the nitrogenfixing nodules of the pulse plant, the Rhizobium. The soft C-shaped, white-coloured larvae with a brown head will feed on the nodules for up to six weeks, sometimes completely destroying them. Without these nitrogen-producing nodules, the plant is weakened, is less drought tolerant and produces less seed.

“It’s not so critical in high organic soils, if the soil produces lots of nitrogen,” Meers says. Should farmers then place more nitrogen with their pea seed? Meers thinks that would be contradictory, as peas are usually planted for improved soil fertility. “The implications of the pea leaf weevil are for this crop and the next one too — it’s more subtle,” Meers says. Farmers should consider that when thinking about pea leaf weevil control. The economic benefits of a healthy pulse crop extend past the current year. The pea leaf weevil is one of the longest living insects. A female pea leaf weevil lays up to 1,500 eggs over a period of three months. Although there is only one generation per year in Alberta, that generation often survives the emergence of the next generation, one year later. The insect is an extremely good flyer, easily covering several kilometres. “The pea leaf weevil has a strong ability to increase in numbers,” Meers says.

photo: alberta agriculture and forestry

PEA LEAF WEEVIL MANAGING PEA LEAF WEEVIL Here are six ways to manage pea leaf weevil, as listed on the Alberta Agriculture and Forestry website. 1.  Plant early to maximize yields and potentially escape the weevil in cold springs. 2.  No-till cropping systems, integrated pest management systems and good crop rotations are recommended. 3.  Use inoculants and adequate levels of fertilizer to maximize crop yields. 4.  Registered seed treatments are recommended if high populations of pea leaf weevil were in the area the year before. 5.  Trap crops can be planted along field borders in the fall or early spring. If warranted, spray trap crops with a registered insecticide to control pea leaf weevils before they move into the main crop. 6.  Scout for pea leaf weevils as soon as peas emerge and continue up to the sixth node growth stage. † Source: Alberta Agriculture and Forestry

» continued on page 4

In This Issue

Wheat & Chaff .................. 2 Features . ........................... 5 Crop Advisor’s Casebook . 6 Columns ............................ 12 Machinery & Shop............. 20 Cattleman’s Corner .......... 26

grasshoppers are back

savings from tracks?

Dilia narduzzi page 7

scott garvey page 23

FarmLife ............................ 31


Turn static files into dynamic content formats.

Create a flipbook
Issuu converts static files into: digital portfolios, online yearbooks, online catalogs, digital photo albums and more. Sign up and create your flipbook.