SpiderMites (red and two-spotted)
Less than a mm in size and able to reproduce in large numbers spidermites have become public enemy number one to the indoor gardener. If allowed to go unchecked these little buggers can completely decimate your crops.Initially a small number of mites will be noticed on the undersides of the leaves as small dark spots, you may also notice some stippling or discolouring of the leaves where the mites are feeding. As their numbers increase they will start covering your plants in webs. Once they start webbing you're looking at a pretty serious infestation that is very hard to eliminate.
Spidermite egg to adulthood takes 14 days at 21 degrees and less than a week at 30 degrees. Adult females can produce 100 eggs over 4 weeks, given this quick reproduction time the spidermite can increase its numbers exponentially which makes it such a menace.
TREATMENT :
- If in flower use SpraySafe or SpiderMite Control until 10days before harvest to keep them under control.
- After harvest completely clean down your grow room, use a bleach based product and thoroughly clean all equipment and the room itself. Make sure to rinse everything afterwards.
- Re-introduce some plants and get them to veg. If using cuttings off plants that had spidermites dunk all plant matter in Pest Off when you take your cuttings. Just don't dunk the base of the stem where you're going to apply your clonex.
- Buy a course of spidermite predators from defenders, their details are at the top of the page. Predators are excellent at eradicating spidermites but only in the veg-phase and only if you can achieve an environment of around 60% humidity and 20 degrees temperature.
- Spray plants, equipment and growroom every 7-10 days with neem repel. Don't start spraying until a few weeks after you've introduced the predators.
Thrips
These very small tan or white insects can attack leaves, flowers, or fruit. They rasp the surface where they feed causing leaves to "silver" and fruit to dry, you'll also see black specks (Thrip fecal material). Only on close inspection is the pest itself found. Thrips will vary in appearance depending on how old they are.Larval thrips (1-5 days old) look like small white yellow worms with tiny legs and move slowly around the leaves.
Prepupa thrips (6-10 days old) begin to grow more yellow or orange in colour and develop legs and wings. They are much more mobile than their larvae and will zip around if you disturb them.
Adult thrips (30-45 days) also known as thunderflies adult thrips are fully fledged winged insects. In our experience thrips very rarely mature to adulthood in an indoor growing environment.
Fungus Gnats
Its usually quite easy to spot when you have fungus gnats as you'll notice a bunch of small grey/black flies buzzing around your plants mostly around potted media. Adults aren't much of a problem but their larvae live in your growing media and can seriously injure the roots of immature plants and especially cuttings.Larval fungal gnats (4-6 days old) small almost translucent worms with a dark patch on their head and bodies. Can grow up to 5.5mm in size prior to becoming Pupae. Found in the top layers of soil, they survive mostly off organic debris like algae and fungi but they will also nibble the roots of new cuttings or seedlings causing quite a bit of damage.
Adult fungal gnats (20-26 days) small flies about 2.5mm in size that resemble mosquitoes and are grey or black in color. Quite delicate, they have long legs and one pair of clear wings. Adult fungus gnats are generally seen flying close to the potting media.
Plant damage symptoms appear as unexpected wilting, low vigor, poor growth, leaves yellowing and defoliation. In most cases your plants will often outgrow them, so they may be more of a nuisance than a real threat to plant health. Severe symptoms tend to be more evident on small plants where roots are much more vulnerable to attack.
TREATMENT: Use Gnat-Off to eradicate larval fungus gnats and Pest-Off for airborne adult gnats.
Last Updated: January 06, 2011
