Spider Mite On Indoor Plants: How To Deal With Pest Flowers At Home Or In The Greenhouse, Methods Of Destruction And Preventive Measures
Recommendations On How To Deal With Spider Mites On Indoor And Garden Plants
- 1 Recommendations On How To Deal With Spider Mites On Indoor And Garden Plants
- 2 What you need to know about the pest?
- 3 Causes of appearance on indoor and garden plants
- 4 First steps when detected on flowers
- 5 How to fight: detailed instructions
- 6 Preventive measures
- 7 Greenhouse Cucumbers
A spider mite is a small pest that often settles in a garden, a vegetable garden or on home flowers. Appearing on a single plant, the parasite infects its neighbors very quickly. Tick control is laborious, as it requires at least 2-3 treatments of the plant.
The article will tell you how to deal with a pest at home or a greenhouse.
What you need to know about the pest?
The parasite feeds on plant sap. Most often settles on the underside of the leaves, wrapping the leaf plate with a thin and almost invisible cobweb.Color pest varies from light green to brown. There are spider mites in all points of the globe, except Antarctica. Scientists distinguish more than 1000 species.
Spider mites are not insects. In insects there are 3 pairs of limbs, and in ticks — 4. These parasites belong to the class of Arachnids.
Causes of appearance on indoor and garden plants
Favorable conditions for life and reproduction — dry and warm air, temperature from +30 degrees and humidity of 35-45%. In apartments, ticks often appear in the winter when they turn on the heating.
The pest can get into the room through the window openings, it can be brought with a new plant or with a new primer for transplanting.
On beds the parasite lives in the old fallen down foliage, and then — creeps on a plant.
First steps when detected on flowers
To detect the presence of a pest can be on a number of characteristics. These include:
- appearance of small discolored dots on the sheet plate;
- growth points to the size of the spots;
- the presence of cobwebs on the back of the sheet;
- leaf rolls up and fades.
Right away After detecting signs of infection, a number of immediate actions should be taken.. The first and obligatory stage is washing all parts of the infected plant with a concentrated solution of laundry soap. This will reduce the number of parasite populations. Next you need to wash and sanitize all the pots and saucers (put in boiling water), window sill, glass, frame and even curtains.
How to fight: detailed instructions
The general algorithm for eliminating the parasite includes the following actions:
- Rip off all wilted and yellowed leaves (by removing them, you can immediately get rid of 25% of parasites).
- Isolate adjacent plants.
- Wash the plants (infected and nearby) with water with soap. Alternative — dishwashing detergent.
- Water the plant with plenty of water (this will wash off the remnants of soap), you also need to shed the soil.
- Put a plastic bag on the pot with the infected plant, put it in a dark place for a few days.
These actions will need to be repeated 2 more times at weekly intervals.
Chemicals can get rid of ticks much faster.. It is necessary to carry out the treatment several times with an interval of 5-10 days. For the destruction of spider mites are suitable insectoacaricides (Fitoverm, Vertimek, Kleschevit) and acaricides (Apollo, Sunmite, Flumayt). See the dosage in the instructions, as the proportions for home and garden plants will be different.ATTENTION! Chemical preparations are used only in accordance with the instructions, since their high concentration can destroy the plant.
Differences and specifics:
Insectoacaricides kill all insects. These are drugs designed to fight simultaneously with harmful insects and mites.
Basically, these drugs are toxic, apply them better on the street or in rooms with good ventilation. The most effective is Actellic and Fitoverm. Acaricides — Chemicals that are used only to combat ticks.
Used to protect cultivated and indoor plants, as well as for the treatment of premises. On some packages there is an inscription «with an ovicidal action» — this means that they will destroy not only adult individuals, but also their larvae.
Folk Methods of Struggle (Table)
If the plant is not in a state of neglect, then folk methods will be safer and more benign.
|Means||Preparation and use|
|Medical alcohol (96%).||
Moisten a tampon or cotton wool, wipe the leaves. Mature ticks will be destroyed, but the larvae will remain.
Alcohol has the ability to quickly evaporate and the leaves should not be damaged. But still it is better not to carry out this procedure with plants that have thin leaves.
|Infusion of onion peel||
|Black henbane infusion||
Spray the plant 2 times a day for 3-4 days with any obtained product.
|Broth from tops of potatoes||
Use for regular spraying.
Processing plants tinctures and decoctions should be carried out in the evening.If the effect is not observed, it is better not to delay and use chemicals.
The main factor for the appearance of spider mites is dry air, therefore the best warning is spraying water on plants during dry weather. At the same time it is necessary to ensure that water does not accumulate in the core of the stem.Pay special attention to plants in the winter season, as due to the decrease in the length of the day and low temperatures, water evaporates slowly.
To get rid of the parasite, the plant should not be immersed in water, because when in contact with water, ticks appear armor in the form of air bubbles.
Homemade solution will help prevent infection.
- To make it you need to mix 20 g of cinnamon, 40 g of Italian herbs, pour 1 l of water.
- Boil, cool and add 40 g of chopped garlic.
- You can also add 2-3 drops of soap.
Nuances of prevention at the site:
- Regular processing of garden tools with disinfectants.
- Digging the soil in the fall.
- During the period of fruiting — regular weeding and subsequent loosening.
- Compliance with crop rotation tips.
- Watering regular (as the earth crust dries), soil mulching.
- Daily inspection of leaves for infection. When detecting traces of the parasite — cut off the infected leaf and burn.
Getting rid of spider mites can be a long and painful task. Try not to create conditions that beneficially affect the reproduction of the parasite. (heat, moisture, dryness).
At home, do a wet cleaning, observe sanitary standards, wipe the dust not only on the cabinets, but also on the leaves. At the site regularly air the greenhouse, time to get rid of weeds.
Biological controls have been used in commercial greenhouse cucumber production in Canada since the early 1980’s. Biological control is most effective when used in an Integrated Pest Management (IPM) program (see Integrated Pest Management). As in any IPM program, success depends upon correct identification of pest problems, regular monitoring, careful timing and integration of complementary control measures. It also depends on good clean-up, sanitation and other measures that remove breeding sites for pests and prevent them from entering the greenhouse.
The primary pests in greenhouse cucumbers are fungus gnats (Bradysia spp.), western flower thrips (Frankliniella occidentalis), greenhouse whitefly(Trialeurodesvaporariorum) and two-spotted mites (Tetranychus urticae). Melon aphid (Aphis gossypii) can be a serious problem in some situations, while other species of aphids, caterpillars and Lygus bugs may also occur.
Challenges for using biological controls successfully on cucumbers are:
• Controlling pests during winter months. When the natural daylength is short it induces
many biological controls to go into diapause.
• Lack of pollen in cucumber crop flowers. This means there is no alternative food
source for biological controls, making them more difficult to establish.
• Chemicals used to control plant diseases. Fungicides to control Pythium root rot and
powdery mildew can interfere with development of biological controls.
The following guidelines contain practical tips for achieving good results against pests in greenhouse cucumbers. Recommended release rates for each biological control are shown in Table 1. More detailed information on pests and biological controls can be found in the separate information sheets for each species.
Start Right with Cucumber Seedlings
IPM for cucumber begins with seedling production. It is important that propagators establish the fungus gnat predator, ‘Stratiolaelaps’ (see Stratiolaelaps) at the seedling stage. Propagators must also supply information about all pesticides that have been used on seedlings. This is important to know as some pesticides can interfere with the later use of biological controls.
If powdery mildew is a chronic problem, consider choosing a mildew tolerant cultivar to reduce the need for fungicide applications that can interfere with biological control.
There are two main ways to monitor for common cucumber pests:
• Trapping pests on yellow sticky cards. These are used to monitor for whitefly, thrips
and fungus gnats. Blue traps are also used for thrips but yellow traps are usually
preferred because they can be used for whitefly as well. Inspect traps weekly; replace
every 3-4 weeks as glue becomes less effective. Place traps at the top of the plant
canopy for whiteflies and thrips; place them about 1 ft (25 cm) above the growing
media for fungus gnats.
• Visual inspection of plant leaves. This should be done weekly for signs of two-
spotted mites, aphid infestations and other problems.
The main pest in greenhouse cucumbers is the greenhouse whitefly (for more informa-
tion see Whiteflies ). Whiteflies damage greenhouse cucumbers by covering fruit and leaves with the sticky honeydew as they feed. High whitefly populations also reduce the vigour of plants. Whiteflies can be controlled by the parasitic wasp, ‘Encarsia’, and the predatory beetle, ‘Delphastus’, by following steps described below.
• Begin in the empty greenhouse, before seedlings are planted out.
• Hang up yellow sticky cards or tapes at the rate of 1 trap/500-1000 ft 2 (50-100 m 2 ).
• Check traps weekly for adult whiteflies.
Release Biological Controls
Both biological controls for whiteflies described below can be used together.
Encarsia: Encarsia formosa is a tiny, 1 mm (1/20 inch) long, wasp that parasitizes immature stages of whitefly. It is sold as loose parasitized scales or scales glued to cards, from which the adult wasps emerge. As the wasp develops inside, greenhouse whitefly scales gradually turn black; parasitized sweet potato whitefly scales turn a tan color. If there is a history of whitefly problems best results are achieved when Encarsia are introduced preventively, at low rates, before whiteflies are found on monitoring traps. Releases continue, usually weekly and are maintained until 80% of whitefly pupae appear parasitized. (For more information, see Encarsia.)
In warm regions or areas where a large number of greenhouses have whitefly infestations, the whiteflies may move onto outdoor plants. This makes them more difficult to control as whiteflies continually re-infest the crop plants. Encarsia are less effective during cool weather and overcast periods, therefore whitefly populations must be monitored closely.
Delphastus: Delphastus catalinae is a small, black, 1/15 inch (1.4 mm) long, lady beetle. Both adults and larvae feed on whitefly eggs and immature stages. Delphastus is sold as adults and should be applied as soon as whitefly are detected. Delphastus works well with Encarsia because it avoids feeding on parasitized whitefly scale (for more information see Delphastus).
• It is essential to start with a clean crop at the beginning of the season, therefore
destroy all crop residues and dispose of them at a site remote from the greenhouse.
• If the previous crop was infested with whiteflies, leave the greenhouse entirely
empty of plants for 5 days, with heat, to starve whiteflies; or, kill them with cold by
allowing the greenhouse to freeze below 14°F(-10°C for) a week.
• If a plant-free period is not possible between crops, use a short-residual fumigant
such as naled (Dibrom©). Apply at the end of the crop, before removing plant debris,
and again to the empty greenhouse. Sprays such as bleach and Virkon used for
disease control will not kill whitefly. Add insecticidal soap or dormant oil to the
spray used to wash down the greenhouse structure and floor between crops to kill
whitefly and other pests that often move to the walls or ceiling or hide in protected
• Keep the greenhouse weed-free, and maintain a 10ft (3m) wide, weed-free border
around the greenhouse.
• Do not keep ornamental plants in a cucumber greenhouse as these are also whitefly
• If greenhouse whitefly numbers are high, hang yellow sticky tapes (up to 1 tape per
plant) at the top of the plant canopy to trap adult whiteflies. If sweet potato whitefly
is present, hang traps about 1 meter below the top of the plants.
• If whiteflies are present on outdoor plants, screen all entry points.
Fungus gnats can cause significant damage in soil-less or sawdust bag cultures. In cucumbers, most damage is caused by the larvae feeding on tender roots and on the lower part of the stems. As root area is lost, cucumber plants become more susceptible to drought stress and root rot infections. Adult fungus gnats can also transmit root rot and other diseases. If the humidity in the greenhouse is very high, fungus gnat larvae may feed on and destroy the growing points of the cucumber laterals. (For more
information see Fungus Gnats).
• Use yellow sticky cards at a rate of 1 trap/5,000 ft 2 (500 m 2 ).
• Place cards about 1 ft (25 cm) above the soil or rockwool surface.
• Check traps weekly and record the number of adult fungus gnats; replace traps
every 3-4 weeks as the glue dries out.
It is important to distinguish between fungus gnats and shore flies because biological controls for fungus gnats do not work on shore flies (for descriptions, see Fungus Gnats).
Release Biological Controls The following three species of biological controls are compatible with each other and can be used together.
‘Stratiolaelaps’: This soil-dwelling predatory mite feeds on fungus gnat larvae. The best way to use Stratiolaelaps is to establish it in the greenhouse before fungus gnats appear. Apply to cucumber seedlings in flats or cubes at the start of the growing season, and then again when planting out. By feeding on other soil organisms, Stratiolaelaps populations can build up to high numbers that are effective in keep fungus gnat populations low. (For more information, see Stratiolaelaps).
Supplement Stratiolaelaps with other biocontrols (below) if fungus gnat populations are high.
Insect Parasitic Nematodes: Steinernema carpocapsae, S. feltiae, and Heterorhabditis spp. are beneficial nematodes sold to control fungus gnats and other insects (see Misc. Biological Controls). They can be applied to the soil through conventional sprayers or through the irrigation system. Nematodes are effective against high populations of fungus gnats but, unlike Stratiolaelaps, will not reproduce or remain in the growing media and must be reapplied.
Apply nematodes when yellow sticky traps average over 50-75 fungus gnat adults
per trap, weekly, or while fungus gnat populations appear to be increasing.
• If root diseases are a problem in the crop, apply nematodes sooner to reduce the risk
of disease transmission by fungus gnat larvae.
• Three applications, 7-10 days apart, are usually required. Nematode products vary,
so always follow product recommendations for rates. Calculate application on the
actual growing area, not greenhouse area.
Note: The actual growing area for rockwool cultures with plant densities of 1.2-1.4 plants/10 ft 2 (m 2 ) is typically 1/3 to 1/4 of the total floor space.
Bacillus thuringiensis israelensis (BTI): A strain of this bacteria that infects fungus gnat larvae is available (Vectobac®). It is applied in water to the soil or growing media after fungus gnats are established (follow instructions on the product label).
• It is essential to eliminate wet spots in the greenhouse where fungus gnats can breed
by improving drainage, repairing leaks in plumbing, adjusting automatic irrigation
• Control is usually better in greenhouses with white plastic floors because fewer
breeding sites are available for fungus gnats.
• Control fungus gnats in other crops in adjacent greenhouses.
WESTERN FLOWER THRIPS (WFT) & ONION THRIPS
Western flower thrips is more likely to be a problem in greenhouses with ornamental plants on site. Thrips damage leaves and distort the fruit of English cucumbers by feeding and laying eggs in leaf and flower tissues and young developing fruit. When WFT populations are high the adults are found in high numbers in the cucumber flowers. Onion thrips will also attack cucumbers but the damage is usually confined to older leaves and is less severe. Adult onion thrips are not as attracted to cucumber flowers and fruit as WFT are (for more information, see Thrips).
• Use yellow or blue sticky cards (using the same yellow cards for whitefly monitoring
saves time) at a rate of 1 trap/500-1000 ft 2 (50-100 m 2 ). Place traps at the top of plant
• Count the number of thrips on traps weekly; replace traps every 3-4 weeks as the
glue dries out.
• Examine a minimum of 20 leaves from mid-plant level in each infested area. Look
for presence or absence of both thrips and Cucumeris predatory mites. When each
leaf with thrips also has predators present, it is an indicator that the thrips population
should begin to decline.
Release Biological Controls
The following three species of biological controls are compatible and can be used together.
‘Stratiolaelaps’: This soil-dwelling predatory mite feeds on the immature stages of thrips in the soil or growing media. Stratiolaelaps alone cannot control thrips infestations, but it contributes to the effectiveness of biological control when used with other predators (for more information, see Stratiolaelaps).
‘Cucumeris’: The predatory mite Amblyseius cucumeris feeds on immature stages of thrips. It is available in slow release bags, which are placed among plants as soon as plants begin to climb the trellis wire. Cucumeris is also available in a loose bran carrier, which is sprinkled onto leaves. Releases should continue until there is a 1:1 ratio of thrips to Cucumeris on leaves as determined by monitoring (see monitoring above). For more information, see Cucumeris.It usually takes 4-6 weeks to see a drop in the number of thrips caught on traps as a result of releasing Cucumeris.
‘Orius’: The tiny pirate bug (Orius spp.), is attracted to cucumber flowers and feeds on all stages of thrips. Orius are only effective from March to September because they do not reproduce if day length is less than 16 hours. Orius should be released once thrips are established, on plants where thrips numbers are the highest in the greenhouse. Release at least 500 Orius at one time to establish a breeding population. For more information, see Orius.
• Avoid thrips re-infestations by thoroughly cleaning up the crop at the end of the
season. Treat the greenhouse with naled (Dibrom®) after the last pick, before
removing cucumberplants, and again after the greenhouse is empty.
•To starve thrips between crops, maintain a heated greenhouse, empty of plants,
which forces adult thrips to emerge from the soil-borne pupal stages.
• If thrips populations were high in the preceding crop, it may be advisable to apply
lime to the ground before covering the greenhouse floor with plastic. Care should be
taken to overlap and tape, or glue, the floor covering together.
• Do not maintain any ornamental plants in the greenhouse, and maintain a weed-free
border, 10 ft (3 m) wide, around the outside perimeter of the greenhouse.
Two-spotted mites are common, important pests of greenhouse cucumbers (for more information, see Two-spotted Mites). During warm weather, TSM populations reproduce very quickly and cause economic damage to cucumber plants.
Controls should be applied at the first sign of TSM infestation, even if the infestation is minimal.
• Inspect leaves under 10-15 X magnification for TSM infestation.
• Some growers usebean seedlings or climbing runner beans as trap plants to detect
the first appearanceof TSM on new crops. TSM damage is easy to see on bean
leaves, which alerts growers that there may be mites on cucumber plants.
Release Biological ControlsTSM can reproduce very rapidly on greenhouse cucumber so it is important to apply biological control agents as soon as mite damage is detected. A combined attack using the three biological controls listed below will provide the best results.
‘Persimilis’: The predatory mite, Phytoseiulus persimilis, is a very effective control for TSM in cucumbers. The predators develop twice as fast as the pest at moderate greenhouse temperatures (for more information see Persimilis).
• When TSM are first seen, introduce Persimilis onto all infested leaves using at least
2000-3000 Persimilis per introduction. If treating a “hot spot”, where TSM numbers
are high, plan to continue releases until predator mites are present on all infested
• Use the Persimilis shipped on bean leaves, rather than vermiculite, because
predators survive shipping in better condition and are easier to apply. Place bean
leaves with Persimilis on cucumber leaves near TSM infestations or on the growing
points of plants. Alternatively, apply the ‘HOT SPOT’ Persimilis product (which
contains high numbers of Persimilis in vermiculite) to each infested site.
• Once Persimilis are established, thousands will be produced on each cucumber leaf.
To speed distribution, pick some of these Persimilis “nursery” leaves and move them
to other plants all around the infested sites and throughout the crop.
• If TSM populations are high (i.e., there are large numbers of mites clustered on webs,
stringing or dropping down from the plants), spray once or twice with fenbutatin
oxide (Vendex®), then release Persimilis when the last spray has dried. Vendex does
not kill the egg stage of the spider mites and will not harm predatory mites.
‘Stethorus’: The tiny, black lady beetle, Stethorus punctillum, is effective at controlling TSM populations and can be used with other biocontrol agents. Stethorus is active over a wide temperature and humidity range, feeds on all stages of TSM and adult beetles fly and are good at finding small colonies of TSM. Stethorus adults are available from suppliers. They should be released in infested sites as soon as TSM are detected. (For more information, see Stethorus.)
‘Feltiella’: The predatory midge, Feltiella acarisuga, may also be used to control TSM on cucumber. Feltiella larvae feeds on all stages of TSM. Feltiella do best when humidity is over 50%RH and at high mite densities. They should be released early in the season once TSM becomes established. (For more information, see Misc. Biological Controls.)
• Chemical control in conjunction with biological control is recommended if mites are
clustering in balls or “stringing” down from the plant or detected in high numbers
without predators present. Fenbutatin oxide (Vendex®) is safe for use with Persimilis,
but check compatibility before using other pesticides with biological controls. (Contact
Sound Horticulture for information.)
• Once Persimilis has been released, maintain warm temperatures (optimum 77°F/25°C)
and high humidity (optimum 80-90% RH) to encourage the predators. Mist the crop if
• It is important to finish each crop with low populations of TSM. High numbers at the
end of the year result in the survival of many red colored diapausing (overwintering
stage) spider mites that will re-infest the next crop early in the season. If mites are
still a problem in late July, a miticide such as Avid should be applied in August to
prevent diapausing mites from over-wintering. Pesticides are less effective against
the diapausing form of TSM present in the fall.
Aphids (such as the melon aphid, Aphis gossypii, can be a serious problem in greenhouse cucumbers. New infestations are usually detected first on cucumber leaves and stems. The melon aphid reproduces very rapidly on cucumber and all three biological control agents listed below should be released as soon as possible.
• Release ‘Aphidius’ parasitic wasp, Aphidius matricariae, (see Aphidius) to parasitize
the melon aphid.
• Release ‘Aphidoletes’ aphid midges, Aphidoletes aphidimyza, (see Aphidius) between
March 15 and August 15, at a high rate, weekly, until aphids are controlled.
• Release the lady beetle, Harmonia axyridis, to control all species of aphids. If the
aphid infestation is widespread, also release field-collected Hippodamia convergens as
well (for more on both lady beetles, see Lady Beetles).
CATERPILLARS (CABBAGE LOOPERS, ETC.)
The caterpillars of several species of moths and butterflies may become serious pests in if their numbers are allowed to build up and should not be ignored.
• Hand pick and destroy any larvae found on young plants; use an ultraviolet (UV)
light trap to catch adult moths
• If intake fans are used, screen with 5 mm (1/4 inch) mesh screen. This will also stop
Lygus and other flying pests.
Release Biological Controls
• Spray Bacillus thuringiensis (Dipel® or Foray®) at label rates every 3 days, for several
weeks, as soon as caterpillars are first detected. Ensure good coverage of both upper
and lower leaf surfaces.
• Trichogramma spp. parasitic wasps (see Trichogramma) attack moth eggs and can
assist in control. Apply weekly for at least 4 weeks or until looper populations are
• Predatory bugs, such as ‘Podisus’ (see Misc. Biological Controls) and ‘Orius’ (see Orius)
attack eggs and small stages of caterpillar larvae.
• The parasitic wasp ‘Cotesia’ (see Misc. Biological Controls) attacks caterpillars and may
be available for release.
Several species of Lygus bugs attack cucumber plants. Their toxic feeding causes abortion or death of the affected growing point.
• Hand pick and destroy any adults or larvae found on the plants.
• Screen intake vents and other large openings with 1/4 inch (5 mm) mesh screen.
Summary of IPM Guidelines Greenhouse Cucumbers
• Treat with naled (Dibrom®) after last picking; wash greenhouse structure.
• Remove crop debris, heat empty greenhouse for 3-5 days.
• Cover floors with white plastic.
• Improve drainage to eliminate wet spots. • Remove all weeds inside and around
• Screen vents where caterpillars or Lygus bugs are problems.
At start of crop:
• Whitefly: Release Encarsia at low rates.
• Fungus gnats and thrips: Introduce Stratiolaelaps at the start of the crop.
When pests are detected:
• Fungus gnats: Apply insect parasitic nematodes, BTI.
• Whitefly: Release Encarsia until 80% of whitefly pupae are parasitized; release
• Two-spotted mites: Apply Persimilis, Stethorus, Feltiella as needed.
• Western flower thrips: Apply Cucumeris as needed; add Orius if thrips numbers high.
• Aphids: Release Aphidius, Aphidoletes and, if aphid numbers are high, Harmonia
and Hippodamia lady beetles.
• Caterpillars: Spray BT, release Trichogramma, use UV light traps for adults
• Lygus: Hand-pick all stages.