Greenhouse insecticides: start with the pest, then the register

Four groups of pests cause most spray decisions in a vegetable greenhouse: whiteflies, thrips, aphids and spider mites. Each needs a different first step, and the Maltese register decides which product is an allowed choice for your crop under cover.

The register is the FSSA list of professional plant protection products, current as at 3 June 2026. For every product it shows the active substance, the product type, the administrative status, the crops and uses, and the expiry date. It has no column for pre-harvest interval, so that number always comes from the product label.

Whiteflies in the greenhouse

The usual species are greenhouse whitefly (Trialeurodes vaporariorum) and sweetpotato whitefly (Bemisia tabaci). Both feed on a wide range of crops and weeds.

Look for tiny nymphs on the underside of leaves, sticky honeydew on leaves and fruit, and black sooty mould. Yellowing, silvering or drying leaves carrying nymphs, and deposits of white wax, are further signs. Reflective mulches can repel whiteflies from vegetable plantings. Yellow sticky traps monitor adults and, at high numbers, reduce them. Parasitic wasps for whitefly are sold for release in greenhouses; a circular hole in a nymph shows a wasp has emerged.

When treatment is needed, choose the products gentlest on natural enemies, such as insecticidal soaps and oils. In the Maltese register, the potassium fatty acid soap FLiPPER is authorised for "Solanaceae (Tomato, Aubergine, Pepper, Chilli, Pepino) (open field & greenhouse)", with an expiry of 13 May 2030. The fungus-based NATURALIS (Beauveria bassiana) covers tomato, sweet pepper and eggplant in open field and greenhouse, and runs to 27 September 2029.

Thrips in the greenhouse

Thrips damage shows as stippling on leaves. Hang blue or bright yellow sticky traps to detect flying adults. Horticultural oils, insecticidal soaps and pyrethrins give temporary control, especially against greenhouse thrips. Onion thrips (Thrips tabaci) feed on vegetables including garlic, onion and pepper. Thrips develop through two feeding larval stages and two non-feeding stages, prepupa and pupa, before they become adults.

The pyrethrin product ECONATUR PROXIS 40 is authorised for "Pepper (permanent greenhouse)" until 15 June 2027. LALGUARD M52 OD, based on Metarhizium brunneum, lists cucumber, melon, watermelon and pumpkin in greenhouse and tomato, aubergine and pepper in open field and greenhouse, to 26 May 2030.

Aphids on greenhouse vegetables

Viruses can infect susceptible vegetables even when aphid numbers are very low, so inspect new growth and transplants before colonies build up. The full inspection routine is in the aphid guide.

The register shows crops, not target pests; the target is on the label. Three flonicamid products are authorised: Afinto, TEPPEKI and TROJAN. All three list tomato in open field and greenhouse and bell pepper in greenhouse; the first two run to 4 November 2029 and TROJAN to 30 November 2027.

Spider mites

Spider mites cause white stippling, and dense webbing appears when numbers are high. Damage is usually most severe in hot, dusty conditions and on water-stressed plants. Do not spray when plants are water-stressed or when it is very hot. Commercial predatory mites, mainly Phytoseiulus species, can be released, and the best results come from avoiding dust and broad insecticide sprays. In a heavy infestation with few predators, a soap spray or a selective miticide first brings the pest mites down, and the predatory mites are released afterwards. Sprays of water, insecticidal oils or insecticidal soaps are also used for management, and sulphur should be used on a plant only after it has been shown safe for that plant in your locality.

BERMECTINE (abamectin) is typed as insecticide plus acaricide and is listed "Only in permanent greenhouse: Aubergine, Cucurbits of edible peel" plus strawberries and tomato, until 20 February 2031. FLiPPER is also registered as insecticide plus acaricide.

Caterpillars and the tomato leaf miner

LITTOVIR, a Spodoptera littoralis virus, covers tomatoes, peppers, aubergines, spinach, lettuce and other salads to 17 June 2027. ISONET T is a pheromone for "Tomato, Pepper, Aubergine (Greenhouse)" to 2 August 2029, and PHEROMAZE TUTA for "Tomato, Aubergine (Greenhouse)" to 30 August 2038. For leaf-mine diagnosis see the tomato pest guide.

Systemic and broad-spectrum products

VERIMARK 2.0 (cyantraniliprole) is authorised "By localised drip irrigation" in greenhouse cucumber, courgette, melon, watermelon, pepper, tomato, aubergine and lettuce, to 14 September 2027. EAGLE (cypermethrin) lists "Tomatoes (field and greenhouse)" to 30 March 2031.

Root-knot and soil pests in greenhouse beds

Three nematicides in the register name greenhouse use. ABAMAX (abamectin) is listed for "Tomato, Pepper, Eggplant, Melon, Cucumber, Zucchini in permament" greenhouse only, to 31 March 2039. NEMGUARD GRANULES, a garlic extract, lists tomato, pepper and aubergine in open field and greenhouse, to 6 August 2029. BioAct Prime DC (Paecilomyces lilacinus 251) lists tomato, pepper, aubergine, cucumber and other vegetables, to 15 March 2029.

Which greenhouse crop has which option

Crop under cover	Authorised entries in the 3 June 2026 register
Tomato	FLiPPER, NATURALIS, flonicamid (Afinto, TEPPEKI, TROJAN), LALGUARD M52 OD, EAGLE, BERMECTINE, VERIMARK 2.0, ISONET T, PHEROMAZE TUTA, LITTOVIR
Pepper	ECONATUR PROXIS 40, FLiPPER, NATURALIS, flonicamid (bell pepper), LALGUARD M52 OD, VERIMARK 2.0, ISONET T, LITTOVIR
Aubergine	FLiPPER, NATURALIS, LALGUARD M52 OD, BERMECTINE, VERIMARK 2.0, ISONET T, PHEROMAZE TUTA, LITTOVIR
Cucumber and other cucurbits	FLiPPER, NATURALIS, LALGUARD M52 OD, BERMECTINE, VERIMARK 2.0, flonicamid

How to read one register row

Take BERMECTINE as the example. The row gives the authorisation number 2020-04-15, the active substance abamectin at 18 g/L, the type "Insecticide + Acaricide", the formulation "EC - Emulsifiable Concentrate", the holder Probelte S.A.U, the route "Mutual Recognition", the status "Authorised", the crop restriction and the pack sizes 0.25, 1 and 5 L. Formulation codes differ between products: ISONET T is a "VP - Vapour-Releasing Product" sold as vapour units, Afinto is a "WG - Water-Dispersible Granule" and LALGUARD M52 OD an "OD - Oil Dispersion".

Expiry dates: read them before you buy

Check the expiry column every time. In the same snapshot BOTANIGARD, a Beauveria bassiana product, shows an expiry of 9/30/2025, which is before the date of the list itself. The authorisation guide explains what a withdrawn product's grace period allows.

Rotating modes of action

Metabolic resistance mechanisms may give cross-resistance between mode-of-action groups, so a rotation plan has to be checked against what is known about the pest and product in question.

Alternations, sequences or rotations of compounds from different mode-of-action groups give sustainable and effective resistance management. Applications are often arranged into mode-of-action spray windows tied to crop stage and pest biology.

Pre-harvest interval and re-entry

The pre-harvest interval is how long after applying a pesticide you must wait to harvest. The restricted entry interval is how long you must wait to reenter the treated area. The register carries neither number, so read both on the label of the exact product before buying.

A checklist before you buy

Name the pest and the crop, and note whether the structure is a permanent greenhouse. The register lists permanent greenhouse and open field separately.
Find the product in the register and read the crop line, the status and the expiry date.
Compare the label of the pack in your hand with the register entry. Label guide.
Record the product, mode-of-action group, date and interval. Record fields.

All products listed here were authorised in the 3 June 2026 snapshot and any product can be withdrawn later; the authorisation guide shows how to confirm a product is still on the list.

Next step

Log counts on the IPM monitoring sheet, read the label rules in the labels guide, and match the pest in the thrips guide.