SPIDER MITES
Spider mites (Tetranychidae family, with the most common found member being Tetranychus urticae) are one of the most damaging pests and can destroy plants quickly when left unchecked. They are tiny, eight-legged arachnids related to the spider and tick.
The term “spider mite” come sfrom their behavior of spinning fine silk webs on infested leaves and new growth.
Adults are normally green or yellow but turn red when day lengths shorten in the autumn. Adults have an oval body, with two red eye spots near the head end of the body. Females usually have a large dark blotch on each side and numerous bristles covering the legs and body. They look sort of like bristly black dots. Their eggs are visible too – they are very tiny, white and are laid closely grouped together.
Spider Mites attack plants by stabbing the underside of the leaves and sucking out the sap, causing the cells to collapse and die. The first sign of spider mite damage is fine stippling on leavesthat looks like many small holes poked with a needle which is clustered around the veins, especially the central vein. As their numbers increase, the number of white speckles on the leaf increases and damaged leaves will take on a whitish or grayish appearance before they die.
Once the spider mites begin reproduction, a distinctive `webbing’ forms, usually under the leaf, on the geniculum or petiole insertion point and then at the growing tip of the plant. The mites disperse from a plant of declining food quality on threads of webbing, and drift or are blown on to other plants.
What makes this pest truly difficult to control is its rate of reproduction. Each female will lay up to 12 eggs per day. Mating is not required for egg production. At 70º F, these eggs will hatch in as few asthree days and will develop into adults in only 14 days. Adult females also have the ability to go dormant for a time after the photo period (daily hours of light) shortens, then re-emerge to lay more eggs a few weeks after the photo period lengthens again. That’s one reason Spider Mites keep reappearing on indoor plants.
PLANT MYTH: High humidity deters spider mites
This myth is based on some truth, in that the ideal conditions for spider mites to develop are dry (this term is used in terms of tropical/greenhouse conditions, so it refers to 50-60% RH, which is likely already higher than most people’s ambient home humidities) and hot (25-27℃/77-80℉)
Under these conditions, spider mites can complete their life cycle from egg -> adult -> more eggs in 3 DAYS. HOWEVER, this does NOT mean they will not be successful in multiplying outside their preferred parameters
As was observed in this Nature paper, the normal RH levels found in most of our homes (30-70%) are more than suitable for mite survival and reproduction
Because of their ability to multiply rapidly in ambient home conditions, spider mites can seemingly appear out of nowhere, and develop resistance quicker than most pests. If you try and fail to kill mites all you are doing is breeding resistant super mites. This chart shows the activity of many commercially available pesticides
|
Active ingredient |
Tradename(link for purchase) |
Price* |
ActivityType** |
Life-cycle activity |
TOXICITY |
||||
|
Eggs |
Larvae/ Nymphs |
Adults |
Bees |
Lacewing |
PredatoryMites |
||||
|
Abamectin |
$90 |
T/C |
X |
X |
Y |
Y |
Y |
||
|
Acequinocyl |
$200 |
C |
X |
X |
X |
N |
- |
N |
|
|
Bifenazate |
$100 |
C |
X |
X |
X |
Y |
Y |
N |
|
|
Chlorfenapyr |
$300 |
T/C |
X |
X |
N |
- |
- |
||
|
Clofentezine |
$285 |
C |
X |
X |
N |
N |
N |
||
|
Etoxazole |
$150 |
T/C |
X |
X |
N |
Y |
Y |
||
|
Fenbutatin-Oxide |
$60 |
C |
X |
X |
N |
Y |
Y |
||
|
Fenpyroximate |
$150 |
C |
X |
X |
X |
N |
- |
- |
|
|
Hexytiazox |
$225 |
C |
X |
X |
N |
N |
N |
||
|
Pyridaben |
$430 |
C |
X |
X |
X |
Y |
Y |
Y |
|
|
Spiromesifen |
/Forbid 4F |
$420 |
T/C |
X |
X |
X |
N |
- |
- |
|
Movento |
$40 |
S/T/C |
X |
X |
X |
N |
- |
- |
|
|
* Price can vary over time **Activity Type Codes: S: Systemic, C: Contact, T: Translaminar Fenbutatin-oxide shows acute toxicity to humans and should only be used by licensed professionals in greenhouse settings |
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Advanced, Systemic Protection for Your Plant Collection
Ensure comprehensive pest control with the only systemic combination miticide and insecticide on the market—Spirotetramat (the same innovative active ingredient powering Movento®).
Spirotetramat is expertly formulated to provide complete and lasting protection against sap-sucking insects (thrips, scale, mealybugs), spider mites, and nematodes, safeguarding both visible and hidden plant tissues.
Key Features & Benefits:
Two-Way Systemic Movement: Moves effectively from leaf-to-leaf and leaf-to-root, ensuring thorough protection throughout the entire plant, including dense foliage, new growth, and root systems.
Broad-Spectrum Control: Highly effective against aphids, whiteflies, scales, thrips, mites, psyllids, and nematodes (root-knot, ring, lesion, citrus, dagger, stubby, and cyst species).
Long-Lasting Efficacy: Delivers durable residual control, continuously safeguarding new plant growth from reinfestation.
Ideal for Integrated Pest Management (IPM): Low risk to beneficial insects and natural predators when used according to guidelines, promoting healthier ecosystems and sustainable gardening practices.
Efficient Low-Use Rate: Concentrated formula allows effective pest control with minimal spray volume, saving time, reducing labor, and ensuring timely, efficient applications.
Unique Mode of Action: Spirotetramat’s distinctive chemistry disrupts lipid biosynthesis in pests upon ingestion, significantly reducing pest populations and plant damage.
Easy & Accurate Application: Convenient amber glass dropper bottle with included pipette ensures precise measurement and mess-free handling.
Mixing & Application Instructions:
0.5 oz of concentrated spirotetramat
Dilution Rates:
Per 100 gallons solution: 60–150 mL (2–5 fl. oz.) spirotetramat
Per 5 gallons solution: 3–7.5 mL (0.1–0.25 fl. oz.) spirotetramat
Per 1 gallon solution: 0.6–1.5 mL (0.02–0.05 fl. oz.) spirotetramat
Application Guidelines:
Shake the bottle well before use.
Mix the appropriate amount with water in a clean sprayer.
Spray thoroughly on all affected plants—including neighboring foliage—to ensure complete coverage (including undersides of leaves).
Reapply every 3 days at least 3 times to completely disrupt the pest life cycle.
Safety & Regulatory Information:
EPA Registration: EPA Reg. No. 264-1050
Harmful if swallowed, inhaled, or absorbed through skin; wear appropriate PPE including chemical-resistant gloves, eye protection, and long-sleeved clothing.
Avoid application near aquatic environments due to potential toxicity to aquatic life.
Store securely in a cool, dry area away from food and out of reach of children.
Pests Controlled:
Spider Mites: Two-Spotted, Strawberry, Desert, Pacific, Carmine, and more.
Thrips
Scale
Mealybugs
Whiteflies: Greenhouse, Silverleaf, Sweetpotato
Nematodes
Psyllids: Potato and Tomato psyllids
Note: Always read and follow the complete label instructions before use. In case of accidental exposure, follow first aid measures as detailed on the Safety Data Sheet (SDS) and seek medical assistance immediately if necessary.
Miticides
● Spirotetramat — is the latest generation miticide and insecticide, offering broad systemic protection against spider mites, thrips, scale, mealybugs and more. Given its recent entrance to the market it works exceptionally well against mites that have developed resistance to other more common miticides. It is active on eggs, larvae, and nymphs and adults. Unlike any other miticide it works systemically, and is absorbed from the soil up to the leaves, as well as from leaf to leaf, and will provide resistance for up yo 30-45 days.
● Oberon SC or Forbid (Spiromesifen) - Forbid is a miticide and ovacide that is active on eggs, larvae, and nymphs and adults. Like Avid it is both contact and translaminar and will provide extended resistance It is quite expensive, retailing around $420 for a gallon
● Avid (Abamectin) - Avid is one of the most popular commercially available miticides. It will control mites and leaf miners as well as suppress aphids, thrips & whiteflies. It is active on larvae, nymphs and adults but is not active on eggs. It is both translaminar and active on contact. Translaminar pesticides are those in which the material (spray solution) penetrates leaf tissues and forms a reservoir of active ingredient within the leaf. It is semi-systemic and works its way through the leaf but is not transported throughout the plant. Avid retails for around $95-100 for an 8oz bottle
● Floramite SC (Bifenazate) - Floramite is active on a wide range of mites and provides quick knockdown with 28 day residual suppression. It is active on all lifecycle stages from egg through adult. It is contact only and not translaminar so you must make sure to thoroughly cover the bottoms of the leaves with this one. Floramite retails for around $85-120 for an 8oz bottle
There are a few non-pesticide options that can control light infestations if caught early but once they have established themselves you should use miticides designed specifically for spider mites or you are in for an uphill battle.
Non pesticide options
● Horticultural oil / dormant oil - This is a mechanical pesticide. It kills mites by suffocating them and so there is no way to develop resistance to it. It is effective if applied routinely several days apart since it only suffocates the mobile stages and not the eggs. It can also be mixed with many other pesticides to increase their effectiveness. It is direct contact only and has no residual effects. Horticultural oil and other oil-based pesticides can damage leaves. They can cause burning or other damage to leaves if applied when temperatures are high (80-85F or higher) or if the leaves are sensitive. Always test it on a couple leaves first before spraying a whole plant
● Soapy water & peroxide - Real soap like dr. Bronner’s or safer insecticidal soap + 3-4 TBSP of 3% hydrogen peroxide per cup of water. Spray on and then use a soft, damp cloth to physically wipe the mites off the leaves. Rinse with plain water. Direct contact only with no residual effect
Insecticides
The only insecticide recommended for mites is Bifenthrin ($70). It is effective for suppressing but NOT controlling spider mites on its own, but is very effective when used in conjunction with the miticides listed above.