Flower strips in arable fields for pests and beneficials

Can you reduce your use of insecticides with in-field flower strips? A trial at our Strategic Cereal Farm East is testing their effect on the diversity and numbers of pollinators, predators and parasitoids. 

Benefits of flower strips - trial summary

  • Start: May 2020
  • End: Ongoing

Objective

To find out whether flower strips affect the diversity, distribution, and number of beneficials and pests in an arable field.

Why are flower strips beneficial to arable farms?

Integrated pest management is an important part of arable farming. Our previous research reported that non-crop habitats are important sources of biodiversity. This trial is looking at whether the results found in research trials are also seen on a commercial farm.

Flower strips attract insects that are beneficial for pollination and pest control. Field margins play an important role in enhancing insect predators and parasitoids. The trial will see if flower strips can help farmers to reduce their use of insecticides.

How is the flower strip trial run?

This field-scale trial uses three fields on the farm:

  • Big Guinea Row:
    • 78-hectare field in the farm standard.
    • Sandy clay loam soil and no flower strips
  • Top 59
    • 39-hectare field with flower strips at the edge of the field.
    • Sandy loam soil
  • Bottom 59
    • 61-hectare field with flower strips within the field and at the field edge.
    • Sandy clay loam soil

Slug monitoring and pitfall trapping

In October and November 2020, and again in March 2021, the field team at NIAB set the slug and pitfall traps. The team used a 100 m transect along each field strip, 1m into the field and 100 m into the field. Every 25 along each transect, the team completed their assessments.

Information on integrated slug control

The field team placed each pitfall trap 30 cm away from the slug traps. For the traps, they used a plastic 520 ml food pot submerged into the ground so that the open end was level with the soil surface. Each pot was partly filled with about 200 ml of a saline solution (30 g salt per 100 ml water) and a drop of odourless washing-up liquid.

Solitary bee nests

Between late spring and early autumn, the team are monitoring mason, leaf-cutter and other solitary bees using bee nests.

These nests are made from 25 nesting tubes placed within a 68 mm round plastic guttering downpipe.  Each nest is cut to 17 mm in length and attached by its centre to a post in the field margin at a height of 90 cm from the ground.

The nests are in the best position for continuous sunlight with the openings facing South to South East. To allow any rain to drain freely, they are angled down slightly.

In late August, the research team will bring the nests in from the field to remove and identify the contents.

How have flower strips performed so far

Crop and flower strip establishment

Crop establishment is poorer in Big Guinea Row, likely due to waterlogging in the field. There was some reddening and chlorosis observed on the winter wheat. The flower strips have established well despite the poor weather in winter 2020. 

Slug monitoring

In October and November, Big Guinea Row (farm standard) recorded the highest number of slugs. In March, no slugs were found in any of the traps. This is probably due to the very dry weather in the weeks before the traps were placed in the fields.

Pitfall trapping

The number and diversity of species in each field reduced at each assessment timing in October, November and March. This is hardly surprising given the cold winter and early spring. Even so, in March, over 78 individual species were identified in five family groups in the pitfall traps.

 

Farm standard

Field edge strips

Field and field edge strips

Species

Oct

Nov

Mar

Oct

Nov

Mar

Oct

Nov

Mar

Grey field slug (juvenile)

X

X

 

X

 

X

Snail

 

X

 

 

Other Coleoptera spp.

X

 

X

 

X

CSFB

X

X

 

X

X

 

X

X

Ground beetle (Pterostichus melanarius)

X

X

 

X

X

 

X

X

Ground beetle (Poecilus cupreus)

X

 

X

 

 

Rove beetle (Aleochara lata)

X

 

X

 

 

Rove beetle (Devil's coach horse beetle, Ocypus olens)

 

X

 

X

X

Rove beetle (Tachyporus hypnorum)

X

 

X

 

X

X

Springtails

X

X

 

X

X

 

X

X

Green springtail

X

 

X

 

X

Purple springtail

X

 

X

 

Fly (red unidentified fly)

X

 

 

X

 

 

X

Fly (Cabbage root fly)

X

 

X

 

X

Fly (House fly)

X

X X X X X X

X

X

Midge

X

X X X X X X X X

Gout fly

X

 

X

 

 

Frit fly larva

X

 

X

 

 

Other Diptera spp.

X

 

 

 

Spider (Money)

X

X

X

X

X

 

X

X

X

Spider (Wolf)

X

X

 

X

X

 

X

X

Other Arachnida spp.

X

 

 

X

X

 

X

Mature earthworm

 

X

X

 

 

Sawfly

 

 

X

 

X

Ichneumonid wasp

 

 

 

X

Parasitic wasp

X

X

X

X

X

 

X

X

X

Ant

X

 

X

 

Flower bug nymph

X

 

X

 

X

Aphid (winged)

 

X

 

 

Aphid (wingless)

X

 

 

 

 

Thrips

 

 

X

 

 

Assessing the benefits of flower strips

In June/July 2021, the field team will assess:

  • Aphids
  • Beneficials in flower strips and crop
  • Weeds and flowers in the crop

Yield

At harvest, the farm will collect combine yield data for NIAB to analyse.

Cost of production

The Farm Economics team will calculate the economic cost of production of the winter wheat in each trial field. Using Farmbench, they will produce costs per hectare and per tonne. The calculations will use:

  • Seed, fertiliser, and crop protection
  • Farm labour, machinery, and equipment
  • The regional average for property, energy, and administration

Previous flower strip trial results at Strategic Farm East

Before the establishment of the flower strips, researchers monitored pests and beneficials on the farm:

  • No two fields were alike in their composition of invertebrate pests and beneficials
  • No two floral strips were alike in their plant species composition.
  • Strips on the same farm were more similar reflecting the soil conditions, species selected, and date of drilling
  • No clear impact of distance into the crop on the number of individual pest or beneficial invertebrates in each species
  • Large differences between habitat types.
  • The cover crops, fallow land, and meadow were different, as were the three grass fields (Big Guinea Row, Top 59, and Bottom 59)
  • Important beneficial predators found

Useful resources

Using flowering seed mixes to support conservation efforts and improve crop management

AHDB Encyclopaedia of pests and natural enemies

Our Strategic Farms are an opportunity to see how to use our research on a commercial farm. Find out more about our Strategic Cereal Farm East Programme

Image of staff member Teresa Meadows

Teresa Meadows

Knowledge Exchange Manager - Cereals and Oilseeds
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