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Identifying and Treating Grow Room Pests

It's likely that however well you run your grow room, at some point, you'll have to deal with grow room pests. Pest sprays and insecticides can be worth looking into for severe infestations, but in many cases, it’s possible to use a natural biological control (predators) to get rid of your pests and return your plants to health. 

The first step to treating your grow room pests is to identify which pest is plaguing your plants. In our experience, the most common pests are Red Spider Mite, Thrips, Sciarid Fly (Fungus Gnats) and Aphids. We’ve put together a guide on how to identify the various pests you may come into contact with, and how to treat them. 

Red Spider Mite - Tetranychus Urticae

 

How Do I Know if I Have Red Spider Mite? 

Spider Mites are really small insects which grow to around 1mm in size. Spider Mites thrive in warm environments with low-to-medium humidity, and have a short reproductive cycle. From egg to adult takes about 14 days at 21°C, and less than a week at 30°C.

Using a magnifying loupe will help you to see them a little clearer. With a smart phone, you can see this with our Phone Scope.

The first signs of a spider mite infection is leaf damage, a fine pale mottling on the upper leaf surface. The underside of the leaves have many tiny yellowish green mites and white cast skins and egg shells. 

As the infection progresses, the leaves will begin to look mottled between the leaf veins and the leaves will start to become dehydrated and curl. As the infestation progresses, you will begin to see fine webbing starting to cover your plants. 

How Do I Treat Red Spider Mite?

You have a couple of biological options when it comes to treating Red Spider Mite - two aggressive predators, and one preventative predator. 

Neoseiulus Californicus is a predatory mite which targets Red Spider Mite and feeds on Spider Mite eggs, nymphs, and some adults. Neoseiulus Californicus can only survive in the presence of Spider Mite, and cannot sustain itself without them. For this reason, it is best used as a Spider Mite cure rather than prevention, and should only be introduced directly to the affected area. 

Another option is Phytoseiulus Persimilis, another predatory mite which targets Spider Mite. It has been used to help control Spider Mite in professionally-grown crops for more than 45 years. Phytoseiulus Persimilis is an aggressive predator, much like Neoseiulus Californicus which actively hunts and attacks Spider Mites at all stages of their development. This should only be applied to an existing Spider Mite population. 

If your Spider Mite infestation is not yet advanced, or you’d like to take preventative measures, you may want to try Amblyseius Andersoni, which can survive without the presence of Spider Mite, and will form a colony lasting upto six weeks. Amblyseius Andersoni is best used as a Spider Mite prevention, rather than a cure, and performs best when introduced to low levels of Spider Mite infestation. 

We also recommend the use of SB Plant Invigorator and Yellow Insect Traps. The SB Plant Invigorator is a gentle soap-based spray, which suffocates and kills adult Spider Mites on your leaves, giving your leaves a boost of micronutrients, and giving your biological predators a better chance of success against the Spider Mite eggs and larvae. Yellow Insect Traps will directly attract any adult Spider Mites, and in doing so draw them away from the plant itself.

Thrips - Thysanoptera 

 

How Do I Know If I Have Thrips? 

Thrips are really small insects which grow to around 1-1.5mm in size. Using a magnifying loupe will help you see them a little clearer. With a smart phone, you can see this with our Phone Scope. 

One of the easiest ways to see if you have a thrip infection is to cut a yellow sticky fly trap into strips and lay them over the top of your pot. If this isn't possible with the pot you're using, sitting a whole trap as close to the pot as possible will work too. 

Thrips cause damage to the plant by piercing and sucking out cells on the leaf surface. This causes silver-grey spots on the leaves, with dark green spots (excretions) and reduces the production of the plant. At high infection levels leaves may even wither and die off.

How Do I Treat Thrips?

Amblyseius Cucumeris is a predatory mite which primarily targets Thrips and will also target Broad (Russet) Mites. Amblyseius Cucumeris feeds on young thrip larvae, and can also survive without the presence of Thrips, and form a colony. For this reason, Amblyseius Cucumeris can be introduced before Thrips have fully taken hold.

We also recommend the use of SB Plant Invigorator and Blue Insect Traps. The SB Plant Invigorator is a gentle soap-based spray, which suffocates and kills adult Thrips on your leaves, giving your leaves a boost of micronutrients, and giving your biological predators a better chance of success against the Thrip eggs and larvae. Blue Insect Traps will directly attract any adult Thrips, and in doing so draw them away from the plant itself.

You may also wish to use Steinernema Feltiae, which will control the soil-bourne pupae of Thrips and the larvae of Thrips (found on your leaves) Steinernema Feltiae is best used as a treatment rather than a preventative but can be used as a preventative with weekly applications to sustain the nematode population.

Sciarid Fly/Fungus Gnat - Sciaroidea 

 

How Do I Know if I Have Sciarid Fly (Fungus Gnat)? 

Sciarid Flies are a difficult pest, especially in young plant material. They can cause damage to seedlings, rootstock and cuttings of many plant species and are one of the most common houseplant pests. 

Sciarid Flies go through seven stages: egg, four larval stages, pupa, and adult fly. Adults are noticed when they appear in large numbers. Eggs are deposited in the soil. Larvae generally eat rotting plant material, algae and fungi that are present in or on the soil. 

Adult Sciarid Flies are small delicate black flies about 3mm long with long antennae and legs. The larvae are legless, about 4-5mm long when fully grown, and have clear segmented bodies and black heads. 

The adult flies are commonly found making short hops over the compost surface, because the juvenile sciarid flies are soil borne, the adults are the easiest way to spot an infection. Placing sticky fly traps over the top of your pot will make it a lot easier to spot. 

Adults can spread fungal diseases but most damage is caused by the larval stage feeding on plant roots making them vulnerable to disease infections such as Pythium and other damping off diseases. 

How Do I Treat Sciarid Fly (Fungus Gnat)?

Steinernema Feltiae is an endoparasitic nematode - a microscopic, worm-like organism which actively searches for their prey (in this case the Sciarid Fly) and forms a colony inside of them. 

The Steinernema Feltiae nematodes feed on the contents of the prey, excreting specific bacteria from their digestive tracts as they do so. These bacteria convert host tissue into products that the nematodes can easily ingest. The larvae then die within a few days. 

Steinernema Feltiae have numerous benefits, and will control the larvae of Sciarid Flies, pupae of Thrips (both soil bourne) and the larvae of Thrips (found on your leaves)

Steinernema Feltiae is best used as a treatment rather than a preventative but can be used as a preventative with weekly applications to sustain the nematode population.

To treat, water the nematodes into your soil, and apply to the foliage of your lower leaves. For best results, split the pack of Steinernema Feltiae nematodes into four and apply weekly to keep nematode populations high. Please note, while using nematodes, do not let your soil dry out too much as this will quickly kill them.

We also recommend the use of SB Plant Invigorator. The SB Plant Invigorator is a gentle soap-based spray, which suffocates and kills adult Sciarid Fly, giving your leaves a boost of micronutrients, and giving your biological predators a better chance of success against the Sciarid Fly eggs and larvae. 

Aphids - Aphidoidea 

 

How Do I Know if I Have Aphids? 

Aphids grow to just ¼ inch as adults, and to the naked eye can be almost invisible. It’s therefore important to check your plants closely and often to make sure you’re on top of any issues that may arise. Species of Aphid can be white, brown, grey, black, yellow, etc. so it’s worth checking closely. As always we’re more than happy to consult on any pest identification issues you may have. 

Aphids will usually congregate around flowers buds, the underside of leaves (particularly young leaves) and shoots. Plant growth can be stunted by Aphids, and leaves may become distorted and the plant generally weak. 

Often, Aphids will deposit a sticky dew-like substance on your plants, which will often darken and become black and noticeable. 

How do I treat Aphids? 

Adalia Bipunctata (Lady Bird Larvae) is a time-tested biological control for many species of Aphid. Both adult lady birds and the larvae will eat the Aphids. Eggs are then laid amongst Aphid colonies. Reproduction for the Aphids is not typical. You should introduce Adalia Bipunctata (Lady Bird Larvae) into highly concentrated areas of Aphid activity before they grow too large, it’s therefore vital that an Aphid infestation is spotted early, particularly around young plantlife. 

We also recommend the use of SB Plant Invigorator and Yellow Insect Traps. The SB Plant Invigorator is a gentle soap-based spray, which suffocates and kills adult Aphids on your leaves, giving your leaves a boost of micronutrients, and giving your biological predators a better chance of success against the Aphid eggs and larvae. Yellow Insect Traps will directly attract any adult Aphids, and in doing so draw them away from the plant itself.

We now stock a number of grow room predators in pre-measured and easy-to-transport quantities. These are live organisms, chilled on site at our Sheffield branch, and ready for collection. 

Our staff are extremely knowledgeable, so if you have a pest problem, they'll be able to direct you to the correct predator for the job. Alternatively, if you're not yet experiencing issues with pests, but want to keep ahead of them, we'll be able to advise which predators and biological controls are best suited for keeping your plants pest-free.

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