Diseases and pests in winter oilseed rape

Rape field
When these pests reappear in spring a rapid action is often required. The following overview shows what to pay particular attention to. Potential causes for important diseases and corresponding possible control measures are listed. In addition a summary of currently registered fungicides and growth regulators in winter oilseed rape is enclosed.

Stem pests

Egg deposition of rape stem weevil

Egg deposition of rape stem weevil

First stem symptoms caused by rape stem weevil

First stem symptoms

Distortion of the stem due to infestation with rape stem weevil

Distortion of the stem due

Cabbage stem weevil

Cabbage stem weevil

Leaf symptoms caused by cabbage stem weevii

Leaf symptoms caused

Scheduling insecticide application against stem pests

Fungicides and growth regulators

Which is the best date for fungicide and growth regulator application in autumn?

Principle: Mistakes made in cultivation cannot be compensated by fungicide treatments.

weak crops as a result of

  • inappropriate seedbed preparation
  • late sowing
  • capping of soil surface that hinders crop to establish after sowing
  • drought after seeds germinate (azoles forward growth of plants)

lush oilseed rape crops (oversupply of N)

  • early and heavy infestation with Phoma lingam
  • sites with frequent black frosts (plants treated with azol show a better winter hardiness)

Date of treatment in autumn

Ideal date of spraying is the six-leaf stage of the oilseed rape (last week of September – first week of October!)
product/application rate

winter hardiness/growth:

  • Ampera 1.5 l/ha
  • Carax 0.5 l/ha
  • Efilor 0.7 l/ha
  • Folicur 1.0 l/ha
  • Orius 1.5 l/ha
  • Tilmor 1.2 l/ha

growth regulator:

  • Ampera 1.5 l/ha
  • Carax 0.5 l/ha
  • Efilor 0.7 l/ha
  • Folicur 1.0 l/ha
  • Orius 1.5 l/ha
  • Tilmor 1.2 l/ha
  • Toprex 0.5 l/ha

fungicide effect:

  • Amistar Gold 1.0 l/ha
  • Cantus Gold 0.5 l/ha
  • Caramba 1.5 l/ha
  • Carax 1.0 l/ha
  • Efilor 1.0 l/ha
  • Folicur 1.5 l/ha
  • Helocur 1.5 l/ha
  • Orius 1.5 l/ha
  • Tilmor 1.2 l/ha
  • Toprex 0.5 l/ha

Effects on yield and cost-effectiveness of fungicide applications in winter oilseed rape in autumn

fungicide applications in winter oilseed rape in autumnZoombild vorhanden

fungicide applications in winter oilseed rape in autumn

Effects of a fungicide application on crop yield and cost-effectiveness in winter oilseed rape in autumn. Annual variation and trend recorded over several years.
Which is the best date for fungicide and growth regulator application in spring?
Principle: Mistakes made in cultivation cannot be compensated by fungicide treatments

crops with a higher danger of lodging

  • raised supply of N (livestock farming)
  • plant density is too high
  • varieties that are less resistant to lodging
development of plants is unevenly (azoles produce a more evenly course of flowering and maturation)

strong infestation with stem pests

  • promotes fungal diseases (Phoma lingam, Botrytis cinerea)
  • reduced lodging resistance
long-time narrow crop rotation (over 25% oilseed rape) and crops developed too well before winter

Date of treatment in spring

Ideal date for spraying is inflorescence emergence stage of oilseed rape (BBCH 39-55; plants 40-50 cm high)

product/application rate

  • Amistar Gold 1.0 l/ha
  • Ampera 1.5 l/ha
  • Cantus Gold 0.5 l/ha
  • Caramba 1.5 l/ha
  • Carax 1.0 l/ha
  • Chamane 1.0 l/ha
  • Efilor 1.0 l/ha
  • Folicur 1.5 l/ha
  • Helocur 1.5 l/ha
  • Moddus 1.5 l/ha
  • Orius 1.5 l/ha
  • Tilmor 1.2 l/ha
  • Toprex 0.5 l/ha
  • Torerö 1.0 l/ha

tank mixture

  • Caramba 0.75 l/ha+Moddus 0.5 l/ha
  • Folicur 0.75 l/ha+Moddus 0.5 l/ha

Effects on yield and cost-effectiveness of fungicide applications in winter oilseed rape in spring

fungicide applications in winter oilseed rape in springZoombild vorhanden

fungicide applications in winter oilseed rape in spring

Effects on yield and cost-effectiveness of a fungicide application in winter oilseed rape at development stage of bud formation. Annual variation and trend recorded over several years.

When to use fungicides against Sclerotinia white stem rot?

Principle: A systematic treatment according to a damage threshold or a forecasting concept is not possible at present!

endangered sites

  • oilseed rape in narrow crop rotation
  • sunflowers within crop rotation
  • valleys (high air humidity)
but: even especially endangered sites remain with a low infestation rate if weather conditions are favourable

date of treatment against Sclerotinia white stem rot

ideal date of spraying is the stage of full flowering (BBCH 65)

product / application rate

  • Amistar Gold 1.0 l/ha
  • Azbany 1.0 l/ha
  • Aziza 1.0 l/ha
  • Cantus Gold 0.5 l/ha
  • Caramba 1.5 l/ha
  • Chamane 1.0 l/ha
  • Custodia 1.0 l/ha
  • Efilor 1.0 l/ha
  • Folicur 1.0 l/ha
  • Intuity 0.8 l/ha
  • Mirage 45 EC 1.5 l/ha
  • Orius 1.5 l/ha
  • Ortiva 1.0 l/ha
  • Proline 0.7 l/ha
  • Prosaro 1.0 l/ha
  • Symetra 1.0 l/ha
  • Torero 1.0 l/ha

Effects on yield and cost-effectiveness of fungicide applications in winter oilseed rape at full flowering stage

fungicide applications in winter oilseed rape at full flowering stageZoombild vorhanden

fungicide applications in winter oilseed rape at full flowering stage

Effects on yield and cost-effectiveness of a fungicide application in winter oilseed rape at full flowering stage. Annual variation and trend recorded over several years.

Effect on yield and cost effectiveness of triple fungicide/growth regulator application in winter oilseed rape - autumn, spring & flowering -

Rape triple fungicide treatmentZoombild vorhanden

Rape triple fungicide treatment

Effect on yield and cost effectiveness of triple fungicide/growth regulator application in winter oilseed rape - autumn, spring & full flowering – Annual variation and trend recorded over several years.

Summary

  • optimal sowing is required for maximum yield
  • control of stem pests is a cost-effective measure in general
  • fungicides and growth regulators have an insurance aspect (with hybrid varieties production related efforts are more likely to be profitable)
  • high oilseed rape yields require a “healthy crop rotation” (25% of oilseed rape)