Our Pest Control Expert, Julian Ives, has spent many years advising commercial growers and gardeners on the subject of safe and efficient natural pest control treatments.

Here he shares his experience on the problems Spider Mite can cause in the garden and how to get the best from the biological control measures we supply... 

Using Spider Mite Killer Sachets
There are two versions of Spider mite killer sachets both contain the predator; Amblyseius sp. This tiny predator feeds on spider mite eggs, nymphs and adults. It will also feed on other mites and thrip larvae. These predators can be applied to plants much earlier than the traditional predator; Phytoseiulus persimlis. This is because it can survive in conditions of lower temperatures and humidity. It also feeds on a variety of food sources.
The indoor sachets are smaller in size but contain the same amount of predators as the larger outdoor sachets. The sachets release predators for up to two weeks.
The Spider mite killer outdoor sachet is waterproof enabling it to be used on outdoor plants such as strawberries and raspberries. Both sachet products have a small hole punched in them that releases the predators over 1-14 days.
Hang the indoor sachets on plants like cucumbers, aubergines, tomatoes or ornamental plants.
For the outdoor sachets hang them over a plant stem on soft fruit or ornamentals. Distribute the sachets evenly amongst plants, for large plants with spider mite ensure that at least one sachet per plant is applied.
Each sachet contains approx 250 predators. For large infestations of spider mite in the summer months it is recommended to also use spider mite killer predators in bottles.

Using Spider Mite Killer Predators
Apply Spidermite Killer predators (Phytoseiulus persimilis) only when spider mites are present on plants. Rotate the bottle gently before dispensing the predators onto infected plants.
Try to apply to infested leaves and growing points of plants, as spidermites migrate towards growing points. Misting plants before application also improves the environment for predators and helps stick the carrier material to leaves.
Apply the predators as soon as possible after receipt. If this is not possible they can be stored in a fridge for 1-2 days. The temperature in the greenhouse or indoor growing area should be above 20.c for the predators to be active. At these temperatures the predator will breed twice as fast as the spider mite and eats the whole life cycle from egg to adult! 
More than one application maybe required if there are high infestations of spider mites on plants.

Appearance and Lifecycle
The two spotted spider mite is also known as red spider mite or the glasshouse spider mite. This is the most common and damaging species found on greenhouse grown plants. It can also be found on soft fruit and ornamentals outdoors. There is also a species that attacks top fruit and orchard grown fruit. Spider mites need temperatures of 12.c or more to be active. The rate of population growth increases as temperatures rise. Spider mites develop more quickly in hot and dry conditions and their development is slowed down in humid conditions.
During summer conditions in a greenhouse, spider mite populations can develop extremely quickly e.g. at 25.c with relative humidity at 55-85%, the life cycle of spider mites can go from egg to egg in less than 10 days. Two spotted mites go through five developmental stages from egg to adult. They are round in shape and are about 0.14mm in diameter. Two spotted spider mites are clear coloured at first, once they start feeding they turn green with two darks spots forming on their body. They are only red in colour when they are going into or coming out of hibernation. This is triggered by shorter day lengths and lower temperatures. During hibernation the spider mites do not feed. Spider mites generally go into hibernation in the autumn and come out of it in the spring.  Female spider mites can lay about 100-150 eggs each depending on the type of plant they are feeding on.

Symptoms and Damage
Spider mites feed on plant tissue and plant sap. This starts as fine speckling on plant leaves, normally on the underside of leaves at first. Eventually leaves go yellow and die. Spider mites also produce webbing when their population level rise and this can cover plants. Spider mites use this webbing to move from plant to plant. They also move from leaf to leaf if plants are touching. Spider mites can totally destroy crops of cucumbers, aubergines and tomatoes if not treated. They are also a threat to ornamentals and soft fruit.

Natural Choice Treatments
Early identification and treatment of spider mites is important. Start checking any overwintering plants in greenhouses early in the year especially when day lengths start to increase. There are safe sprays such as Savona for controlling spider mites early on or for treating hot spots later in the season. Biological control can be achieved using tiny predators of spider mites. Amblyseius sp. in spider mite killer sachets for early treatments and Phytoseiulus persimilis in spider mite killer bottles for curative treatments in the summer.