Red Spider Mite Control

Red Spider Mite (RSM) is a major pests under-glass, especially in conservatories / greenhouses / growrooms / hydroponic systems where the combination of high temperatures and low humidity are ideal for their development. In heated enviroments their lifecycle can soon become modified, so they are active all year long.

Adult RSM are just visible to the naked eye and can be found on the underside of leaves although the yellowing of leaves and webbing are normally spotted 1st. Despite their name RSM 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. RSM feed 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. To control Red Spider Mite :-

  • 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.
  • Use Ladybird Larvae to clear HEAVY infestions of spider mites in your greenhouse / conservatory. Once they have cleared the infestation, introduce Phytoseiulus / Ambleyseius Andersonii to give on-going control.