ISSUE #381

381 - Crop Management Options for Increased Profits

5-16-2000

This issue of the Ag Notes includes useful crop management strategies for shareholders to consider. These strategies involve recommendations involving stand establishment, insect and disease, and weed control Gold Standards.

The weed control Gold Standard is "Timely Weed Control to Maximize Crop Potential." Strategies to keep in mind include:

  • Increasing rates of Betamix or Betanex from 8 oz. to 12 oz. as beets reach the 4-leaf stage.
  • Increasing Progress rate from 5.7 to 8.7 oz. as beets reach the 4-leaf stage.
  • A Switch to Betanex as Redroot Pigweed becomes the predominant weed.
  • Where dry conditions prevail use MSO or MSO/Basic blend mixtures for best weed control.
  • Use rotary hoes and harrows where appropriate to save herbicide costs.
  • Consider a layby application of Treflan, it can be tank mixed safely with microrates on 2-inch tall or larger beets. (Injury from Treflan is possible if a period of wet weather follows application).
  • Eliminate unnecessary cultivations.

381.1

Summary of NDSU/U of MN Research

Cultivation caused significant sugarbeet yield loss in three of ten observations at Fargo and Crookston over three years. Cultivated sugarbeets never yielded significantly more than uncultivated sugarbeets.

  • Cultivation is essential if herbicides fail to control weeds.

Plant Population Management

  • Strive for plant populations of 160 beets/100’ of row.
  • Consider thinning stands in fields with more than 175 beets/100’ of row.
  • Don’t replant early planted fields with more than 60 beets/100’ of row.
  • Contact your agriculturist for assistance with replant and thinning decisions.

Post Planting Insecticides for Root Maggots

Sugarbeet root maggot populations were very high in some areas of the Drayton factory district in 1999. Populations are predicted to be as high or higher in 2000 (figure1) according to NDSU entomologists.

Sugarbeet Root Maggot Population Forecast
381.2

Fig. 1. Predicted sugarbeet root maggot population levels for the 2000-growing season in the Red River Valley of Minnesota and North Dakota.

Factors Increasing Need For Second Insecticide Applications

  • Producing beets in high maggot pressure areas.
  • Very early planting and loss of insecticide activity.
  • When low rates of insecticide were used at planting.
  • Fields where wind erosion may have moved insecticide off the row.
  • Always reapply insecticide if replanting a field.
  • Repeated use of these products increases chances of insecticide resistance development.

Apply second applications in late May or early June. Contact your agriculturist for root maggot fly monitoring data to assist in timing applications. Post emergence granular and liquid insecticides increased recoverable sugar per acre by 300 to 1000 lbs./acre under high maggot pressure at the NDSU St. Thomas research site in 1999, (Table 1.)

Table 1: Yield, and gross economic return using planting-time and postemergence applications of granular and liquid insecticides for control of the sugarbeet root maggot, St. Thomas, ND, 1999. M. Boetel, NDSU.

Treatment NameRate (lb ai/A)Appl MethRec. SucroseGross Return
PrePostPrePostPrePost(lb/A)($/A)
Temik 15G Lorsban 15G 1.05 1.05 M B 6090 a 551 a
Counter 15G Lorsban 15G 1.05 1.05 B B 5531 ab 499 ab
Temik 15G Counter 15G 1.05 1.05 M B 5311 a-c 490 a-c
Counter 20 CR Thimet 20G 1.05 1.05 M B 5241 a-d 465 a-d
Temik 15G -- 1.5 - M - 5096 b-d 473 a-d
Counter 15G Thimet 20G 1.05 1.05 B B 5070 b-d 442 b-d
Counter 15G Lorsban 4E1 1.05 0.5 B B 4495 c-e 413 b-e
Counter 15G -- 1.5 - B - 4472 c-e 394 c-e
Lorsban 15G -- 1.5 - B - 4434 de 377 de
Counter 15G Lorsban 4E 1.05 0.5 B B 3847 e 316 e
Check -- - - - - 3645 e 311 e
               
LSD (0.05)           850.1  

1 Applied at peak fly and 1 week after peak fly.