The November issue of the Teagasc Tillage Newsletter confirms the imperative for cereal growers to maintain control over slugs and barley yellow dwarf Virus (BYDV) infections.
Slugs were a major pest problem last season. While sowing conditions have been better in 2024, it is important that growers should monitor for slug damage.
Fields following oilseed rape (OSR) or those with a history of slug damage are most at risk. Where you suspect slugs, lay down traps using a plastic bag or slate with muesli underneath to attract them. Monitor the traps daily to quantify the populations.
Slugs
If four or more slugs are picked upper trap on average, treatment is warranted on emerging or struggling crops. Slugs are most active at night, so the best time to check traps is early in the morning.
The only cultural control option, where slugs are concerned, is rolling – that’s if crop and ground conditions are suitable.
Chemical control will be based on products containing metaldehyde or ferric phosphate. It is important to use the recommended rate on the label.
Applying reduced rates reduces the number of baiting points, resulting in poorer control. It is better to apply one full label rate than a reduced rate twice.
Meanwhile, recent Teagasc BYDV experiments on the early planting of winter barley have confirmed a number of significant trends.
First off, early sowing increases BYDV risk. Significantly, later sowing gives similar or better yield than early sowing where BYDV is a risk.
In addition, selecting a tolerant variety reduces risk of yield loss to the disease with sown early crops where BYDV is present.
Other important factors to consider when assessing BYDV risk are mild weather and whether a ‘green bridge’ is present or not.
Volunteer cereals and grasses are host species for the grain aphid.
Insecticide application should be targeted. Cereal crops emerging in November are at a much lower risk of BYDV than those that emerged in October.
Growers should check if aphids are present in the crop: headlands are a priority in this regard.
Aphids are three times more likely to land near headlands than further out. If they are present, growers apply an insecticide at the 2-3 leaf stage of the crop.