Soil Insect Score

Soil insect score is a measure of the presence of potential insect pests spotted within your soil. The scoring lists some example insect species which may not be relevant to your soil type or environmental biome, so feel free to use these loosely as examples and score your soil based on your own knowledge of insect pressure and damage on your farm.

You can do this test alongside other spade tests, such as earthworm counts.

What to record


  • A score of 0-2 where:
    •  0 = Very poor. E.G. 3+ soil caterpillars, wireworms, leatherjackets, or mole crickets, 4+ cicada, 14+ clover/alfalfa root weevils / grass grubs, or > 40% soil cover of pasture mealy bug.
    • 0.5 = Poor. E.g. 2 soil caterpillars, wireworms, leatherjackets, or mole crickets, 3 cicada, 11-14 clover/alfalfa root weevils / grass grubs, or 30-40% soil cover of pasture mealy bug.
    •  1 = Moderate. E.g. 1 wireworm, leatherjacket, mole cricket, soil caterpillar, 1-3 cicada, 5-10 clover/alfalfa root weevils, 7-13 grass grubs, or 10-30% soil cover of mealy bugs.
    • 1.5 = Good. Minimal / low insect numbers, below economic thresholds.
    • 2 = Very good. No insect pests spotted in the soil sample

Equipment


  • Spade
  • Optional: tray / box to put soil into

How to do the test

1. Dig a 20cm spadeful of soil at your sample location (this can be done with other spade tests). It may be useful to put the soil in a box or tray to make it easier to look through. 

2. Look through the soil, pulling it apart with your hands, counting and recording photos of the insect pests spotted in your spadeful of soil.

3. Record the numbers of insects found in the notes and score your sample in Soilmentor based on the scale above. 

4. Put the soil you dug up back down the hole once you’ve finished!