20 January 2021
Controlling Red Spider Mite under-glass NATURALLY
Red Spider Mite (RSM) is a major pests under glass & can be a particular problem in conservatories where the combination of high temps & low humidity in the summer are ideal for their development. In a conservatory their life-cycle can become modified to last all year long as in an artificial environment they will receive extra light and heat. To control RSM :-
- Use Red Spider Mite Wax Traps to trap / monitor adult red spider mites.
- Use Amblyseius Andersonii when the temp is above 10c or above 30C. Amblyseius Andersonii is supplied in sachets with food, so it is ideal for use early in the season / late in the season when the numbers of RSM are low and when temperatures are too low or or too high for phytoseilus.
- Use Phytoseilus when RSM is active and the temp is between 16C/61F & 30C/86F.
Adult Red Spider Mite (RSM) are just visible to the naked eye and can be found on the underside of leaves. Despite their name they can be any colour from red, yellow, green, orange, brown or even black depending on the host plant, although they are normally red and all have 2 dark spots on the rear of the body. The females over winter in cracks and crevices in greenhouses or conservatories and emerge to lay eggs in the spring when the temperatures rise and the daylength increases. The eggs hatch to produce larvae and as the temperatures rise the infestation can quickly escalate and get out of control. All the stages in the RSM cycle feed on the underside of leaves.
Red Spider Mite feeds on plant tissue piercing the cells and sucking out it’s contents killing it. This occurs mostly on the underside of the leaves resulting in small yellow / white spots to appear on the upper leaf surface. As the attack continues the death of more and more cells causes the leaf to turn yellow and die. Eventually the whole plant is killed. As the number of RSM increases, webs are produced across the shoot tips. RSM can be brought into the greenhouse or conservatory either on plants, on the clothing of people or through vents in warm weather.
Red Band Spider Mite Traps™ are the simple and effective way of trapping / monitoring adult red spider mites. It works on the very simple basis that red spider mites always climb upwards searching for food and this trap uses this behaviour to lure the mites onto a very sticky waxed pad suspended above the plant with a string trailing down into the top of the plant. They are ideal for :-
- Controlling red spider mite throughout the year i.e. including early / late in the season when temperatures are not warm enough for a natural predator such as Phytoseiulus or Amblyseius andersonii.
- For monitoring crops i.e. leave the traps in place and once adults are spotted, natural predators can be introduced.
- Long term protection – leave these traps in place to give on-going control and only need to be replaced when full. N.B. Can even be used when natural predators are already in place to give added protection.
Simply suspend the very sticky wax Red Band Spider Mite Traps™ 30cm / 12″ above the plant with the string trailing down into the top of the plant and as the mites move to the top of the plant, they continue climbing up the string dangling from the trap and onto the sticky wax pad from which there is no escape! The sticky pads only need to be replaced when they are covered in red spider mites, so it is a very simple and cost effective method that works! Be careful the trap is very sticky, so suspend it in the right position before removing the protective backing and keep it away from heaters and lights. Ideal for tomatoes, cucumbers, oranges, lemons and plants in hydroponic systems. Available in packs of 5 – use one trap per infected plant.
Amblyseius Andersonii is a LOW / HIGH temperature Red Spider Mite predator, which is much more tolerant of extreme temperatures – use it when the temp is above 10c or above 30C. Amblyseius Andersonii is supplied in sachets with food, so it is also ideal for use early in the season / late in the season when the numbers of RSM are low. Use Amblyseius Andersonii to control RSM as follows :-
- Early in the spring to control over-wintering RSM – position sachets of Amblyseius andersonii in your greenhouse / conservatory in the spring as soon as the daytime temp is 10c to catch any RSM as they emerge from cracks and crevices in your greenhouse or conservatory as the temperatures rise.
- Use it throughout the growing season if RSM numbers are low.
- Late in the season to clear RSM, which has flourised during the summer – female RSM will over-winter in the cracks and crevices of your greenhouse / conservatory, so if you have had an RSM infestation during the year, position Amblyseius andersonii in your greenhousebefore the temp drops below 10c to stop any RSM from over-wintering.
- Use Amblyseius Andersonii during hot summers – use Amblyseius Andersonni when temperatures are too hot i.e. over 30C for traditional RSM controls such as Phytoseiulus.
Amblyseius Andersonii is supplied in sachets with each sachet containing a colony of Amblyseius and a supply of food, which will last them for up to 6-8 weeks, so it is ideal for using when RSM numbers are low i.e. early or late in the season or if you have a persistent RSM problem each year and you want to introduce a preventative predator. During this time the adult Amblyseius will emerge and search for RSM on your plants to eat. If there are none they will search out other sources of food such as pollen, fungal spores and plant sap and wait for the red spider mite to arrive. Hang approx 1 sachet per plant i.e. 20 sachets is enough to treat the average greenhouse (10 x 6).
Phytoseiulus has been used commercially since the 1960’s to effectively control RSM and now you can use it to control RSM on your plants. Phytoseiulus is a tiny mite, slightly smaller than a RSM and it feeds on all stages of the RSM eating up to 5 adults or 25 young larvae/eggs per day. Control Red Spider Mite by introducing Phytoseiulus AS SOON as you see RSM and the temp is 16°C/61°F (& below 30°C/86°F). Phytoseiulus is a tiny, harmless mite with a BIG appetite for Red Spider Mite, which is used commercially. Ideal for use in conservatories / greenhouses / growrooms / hydroponic systems. Phytoseiulus is supplied in small tubes containing 1000 or 2000 adults. The contents of the tube (inc. the vermiculite they are packed in) is simply sprinkled over the infected plants. If the infestation of RSM is very heavy and there is webbing at the tips of the plants, break up the webs first with your fingers or with a feather duster and spray the plant with SB Invigorator, concentrating on the underside of the leaves. Help the Phytoseiulus by increasing the humidity (spray the underside of the leaves with soft water) and keep the temperature above 16°C (but below 30°C). Also group infected plants together, so the Phyto can “chase” the RSM from plant to plant.
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