Where Irish strawberries are grown
Most strawberries are now grown under cover, using either tunnels or glasshouses. Most crops stand on tabletop systems: steel gutters raised about 1.5 m off the ground, which improves air circulation in the crop. The gutters also collect the leachate for reuse. Plants grow in substrate modules, fed water-soluble fertiliser by drip-line irrigation through an injection system.
Cold-stored plants set out in late spring and summer begin to fruit about 60 days later, which is known in the trade as 60-day production. The earliest cropping needs a modern glasshouse with a computer-controlled environment, and the Spanish tunnel is the most popular polytunnel type, used mainly from May to September.
Strawberries are the main soft fruit crop in Ireland, worth an estimated €47m a year, and the leading cultivar is Malling Centenary. Ireland produces at least 8,000 tonnes of fresh strawberries a year, and the season now runs for up to 10 months. All growers must operate under the food hygiene programme of DAFM and are encouraged to join Bord Bia's Origin Green sustainability programme.
First identify the problem, then look for a product
Before looking for a product, write down what you see: which plant part is affected (flower, fruit, leaf or root), how it looks, how it is spread across the crop, and how it changes over a few days. Take photographs and note where each was taken. Use the same bed, bay or bench references every time, so the next check looks at the same place. Keep what you observed separate from what you suspect: a diagnosis is a guess until someone confirms it.
Insect pests, Botrytis and powdery mildew are listed in separate sections of the directory, so choose the section by the symptoms you actually saw. There is no single best pesticide for strawberries: the right product is the one approved for your pest or disease, on your crop, at its growth stage. Also note the variety, crop age, whether the crop is outdoors or under cover, and which field, tunnel or bay it is. Batches picked on different schedules should be recorded separately.
Thrips: the pest that growers recognise too late
Western flower thrips, Frankliniella occidentalis, caused considerable damage to protected strawberry crops and is a serious pest of main crop and 60-day crops. The main problem is that some growers do not identify it until visual crop damage appears.
The pest is minute, usually brown or black, with a very slender body and two pairs of fringed wings. A dozen or more can sit deep in a strawberry flower among the florets. It has many generations a year, and warm weather can cause a huge explosion in the population in June and July. The female causes most damage: she pierces plant cells to suck sap and lays eggs with a saw-like ovipositor into the young fruitlet, which leads to misshapen, discoloured, unmarketable fruit.
Because the damage shows on the fruit only after the thrips have done their work, look inside the flowers as well as at damaged berries. Do not assume every discoloured or misshapen berry has the same cause; if you are unsure, ask your adviser to look and record where and when the first signs appeared.
Control by IPM with the predatory mite Amblyseius cucumeris is quite effective, but the predator must go on at the very early stage of thrip attack or control will be difficult. Insecticide options are spinosad (Tracer) and abamectin (Dynamec); the timing of application is crucial.
If you use predatory mites, write down what was released, where and when. Before spraying any product in a crop where beneficial insects are working, ask the supplier of the beneficials whether that exact product is compatible with them, rather than relying on a general claim that it is safe for beneficials. Ask again whenever the product changes.
Fungicide for strawberries: what Teagasc research tested
Teagasc research at Wexford on grey mould (Botrytis cinerea) of fruit used outdoor and protected polytunnel crops, with the goal of reducing chemical usage through decision support systems, modified films and biological control agents.
Spraying is only one part of disease control. If you also change something in the crop, such as hygiene, water management or the tunnel environment, record it next to the spray record, because a spray diary alone does not show that work. Note what changed before the problem appeared; your adviser will ask.
Botrytis fungicides for field strawberries
The directory is a starting point for questions, not a spray instruction. Read each row column by column: disease or pest, active substance, product name and PCS number, dose per application, total dose, number of applications, harvest interval and any use-by date. Open the label or EAMU link before you pick a candidate, and treat an empty cell as a question to ask rather than a value to assume. Check that the label covers the way you grow, field or protected, and the pest or disease you identified. A harvest interval or dose limit of one product does not carry over to another product in the same list.
The Teagasc field-strawberry directory lists these products against Botrytis (grey mould). Problad, an aqueous extract of germinated seeds of sweet lupin (PCS 06811), is applied at 3.2 l/ha with a 0-week harvest interval. Serenade ASO, based on Bacillus amyloliquefaciens strain QST 713 (PCS 03847), is applied at 8 l/ha with a 1-day interval. Prestop contains Clonostachys rosea J1446 (PCS 06486).
Boscalid with pyraclostrobin is sold as Bigalo (PCS 06250), Cobalt (PCS 06413) and Signum (PCS 03799), each at 1.8 kg/ha with 3 days before harvest. Cyprodinil with fludioxonil is sold as Botrefin (PCS 06480), Clayton Gear (PCS 06607) and Switch (PCS 06414), each at 1.0 kg/ha and 2.0 kg/ha in total, with 3 days. Fenhexamid is sold as Teldor (PCS 02003) at 1.5 kg/ha, 6 kg/ha per season, 1 day. Pyrimethanil is sold as Pirim (PCS 06268) and Scala (PCS 03916) at 2.0 l/ha, with 3 days.
Keep your spray records in one place. Free to start.
For powdery mildew the directory lists Problad and a long list of azoxystrobin products. Amistar (PCS 05072), for example, is applied at 1.0 l/ha, 3.0 l/ha in total, with 3 days before harvest.
Signum on strawberries: rate, timing and number of sprays
Signum combines boscalid with pyraclostrobin. For outdoor and protected strawberries the Irish label allows 1.8 kg/ha per application and 3.6 kg/ha per year, with 3 days before harvest.
For optimum control of grey mould, Signum goes on as a protectant spray from the beginning of bloom (white bud); for powdery mildew and blackspot, before disease symptoms appear. Applications are made in sequence with other products as part of a fungicide spray programme applied during flowering at 7–10 day intervals. The label allows no more than half of the season's fungicide applications to be Signum, no more than two applications per crop outside brassicas and blackcurrants, and no consecutive applications.
The label lists grey mould (Botrytis cinerea), powdery mildew (Sphaerotheca macularis) and blackspot (Colletotrichum acutatum) for strawberry, with reduced levels of control on protected strawberry likely for the listed diseases.
If you take a product to your adviser, take its label and the disease table with it, and match the disease you found to the entry for that disease before choosing the product. For another formulation, repeat the check with its own documents.
Insecticides for strawberries in the directory
For aphids the directory lists Flipper (PCS 05027, 10.0 l/ha), Benevia 10 OD with cyantraniliprole (PCS 05354, 0.75 l/ha, 1 day before harvest), Decis Protech with deltamethrin (PCS 05269, 500 ml/ha, 3 days) and Tec-Bom, a fatty acid potassium salt (PCS 05040, 11.5 l/ha).
For caterpillars it lists Lepinox Plus, based on Bacillus thuringiensis subspecies kurstaki (PCS 05254, 1.0 kg/ha), and Karate Zeon with lambda-cyhalothrin (PCS 04084, 125 ml/ha, 3 days), besides Flipper, Decis Protech and Tec-Bom. Red spider mite is listed against Flipper and Decis Protech. Black vine weevil is listed against Lalguard M52 GR, a Metarhizium anisopliae granule (PCS 04811).
Which herbicide is safe for strawberries? The 14 products listed
The directory lists 14 herbicides for strawberry plants, each with the same individual and total dose.
Against grasses: clethodim as Centurion Max (PCS 04948) and Dedalus (PCS 07399) at 2.0 l/ha and Lightning (PCS 06644) at 1.4 l/ha, each with a 30-day harvest interval; cycloxydim as Stratos Ultra (PCS 04936) at 4.0 l/ha with 6 weeks; propyzamide as Barclay Propyz (PCS 04006), Barclay Propyzaflash (PCS 04007), Kerb Flo (PCS 02830) and Solitare (PCS 04219), each at 3.5 l/ha.
Against other weeds: isoxaben as Flexidor (PCS 04963) at 0.4 l/ha; napropamide as Devrinol (PCS 05234) at 7.0 l/ha; pendimethalin as Anthem (PCS 04761) at 3.3 l/ha, Clayton Stream (PCS 07405) at 2.9 l/ha, Pendifin 400 SC (PCS 05731) at 3.3 l/ha and Stomp Aqua (PCS 03750) at 2.9 l/ha.
Harvest intervals in the directory
Match each application to the beds or bays that will be picked next. Keep a simple schedule of what is being picked and what is awaiting assessment, and note the treatment history of each, so a picking team does not enter a block that was sprayed too recently. If only part of the crop was treated, record the boundary rather than one reminder for the whole holding. If a record is corrected, check which picking or access notes relied on the old version. The pre-harvest interval records guide covers how to keep these notes.
The harvest interval of the listed fungicides and insecticides runs from 0 weeks (Problad) and 1 day (Serenade ASO, Teldor, Benevia 10 OD) to 3 days for most others. Among herbicides, clethodim products carry 30 days and Stratos Ultra 6 weeks.
Weeds: ask separately from disease control
Before choosing a herbicide, identify the weed, the crop stage and where the treatment will go. A fungicide list or a disease diagnosis is no basis for a weed decision. Keep establishment work, inter-row management and treatment of the cropped area apart in your notes, and check that the product has an authorised strawberry use. If you decide on a different method, such as hand weeding, record it with the reason, so next season's review can compare the weed problem and the result.
Organic pesticides for strawberries
The EU list of products authorised in organic production is updated from time to time (Commission Implementing Regulation EU/2021/1165). The Irish Organic Association standards have separate sections on weed management (2.12), pest management (2.13) and disease management (2.14).
The DAFM pesticide database can be searched by product name, active substance or function/crop.
For a natural or biological product, note its full marketed name, manufacturer and formulation, and for a microorganism the identity named by the manufacturer, not just "beneficial bacteria". Check it against the Irish register for strawberries: a product sold for ornamentals or in another country does not answer the question. If you farm organically, ask your certification body about the exact product and keep its answer with the crop file.
Next step
Identify the pest or disease and note how the crop is grown, then look up the authorisation of the product in the Irish pesticide register.