The predatory mite Phytoseiulus persimilis probably originates from Chile, but has currently been spread by man, on purpose or accidentally, throughout large areas of the world. A Phytoseiulus mite deposits her eggs in or close to a spider mite colony. They are distinguished from spider mite eggs by their oval shape, the light orange colour and because they are twice as big.

The larva, which has 6 legs, does not eat. Similarly to spider mites, the larval stage is followed by the protonymph, the deutonymph and the adult stage. Between the subsequent stages there is no quiescent stage. Once an adult, it takes at 20°C (68°F) about 2 days before the predatory mites start laying eggs. Under normal circumstances, the development time is shorter than for spider mites, and takes about 5 days at 30°C (86°F), 9 days at 20°C (68°F) and 25 days at 15°C (59°F).

Without fertilization the female cannot lay eggs. At 20°C (68°F) she deposits about 54 eggs during 22 days, but this can mount up to 75 eggs. So, under normal circumstances a Phytoseiulus population grows faster than a spider mite population. At higher temperatures (above 30°C or 86°F) or at dry weather (humidity below 60%) the spider mite is favoured and biological control is difficult. At low humidity the egg of the predatory mite shrivels.

The menu of Phytoseiulus nearly exclusively consists of spider mites. Only in case of lack of food the predatory mite eats its relatives. An adult Phytoseiulus devours all stages of spider mites, while Phytoseiulus nymphs only feed on spider mite eggs, larvae or protonymphs. The daily consumption of an adult Phytosiulus amounts to about 20 spider mite eggs or larvae, 13 protonymphs or 5 adults.

Although Phytoseiulus nymphs still stay at the same spot, adults readily move to other hot spots. If the plants touch each other, the predatory mite can spread relatively easily in the crop.

Phytoseiulus can be applied on several greenhouse vegetables and ornamentals such as sweet pepper, cucumber, melon, eggplant, strawberry, bean, gerbera, rose and several pot plants. On tomato Biobest advises the use of the specially developed Phytoseiulus-T-System. For a successful biological control it is important to detect the pest presence on time and to act immediately. As a spider mite population grows faster in summer and it is then more difficult to keep pace with it, it is advised to control them early in the season as soon as the first spider mites wake up from hibernation.

After detecting the first spider mite hot spots, Phytoseiulus is released as soon as possible. Depending on the crop and the circumstances, an overall introduction of 3-6 Phytoseiulus/m² is advised. On and around the infested plants approximately 20 predatory mites/m² are released.

In order to be sure to obtain a biological balance early in the season, some growers prefer the Pre-Phytoseiulus-System. This consists of one tube of Phytoseiulus mites and two tubes of spider mites. On one plant two doses of spider mites are released on two different spots. In one of both introduction spots, one dose of Phytoseiulus is added. The predatory mites first exterminate the first spider mite colony, and then go looking for other spider mite colonies. Thanks to this early balance spider mite hot spots are kept down as from their emergence.

In normal conditions Phytoseiulus is able to protect the crop from spider mites for the rest of the cropping season. However, at dry and warm weather problems can still appear. Experience has shown that in this case, the control activity of Phytoseiulus can be supported by creating high relative humidity by spraying water with high pressure and through a fine nozzle.

Together with Phytoseiulus, growers can now also control spider mites with the gall midge Feltiella acarisuga. A final option are chemical corrections with selective acaricides such as fenbutatin-oxide (Torque), hexythiazox (César, Nissorun, etc.) or clofentezin (Apollo).

Phytoseiulus persimilis is supplied in tubes of 1.000 or 2.000 predatory mites (nymphs + adults) mixed with vermiculite. The screw cap of the tubes has a small hole, through which the material is sprinkled.

	Introduce the predatory mites as soon as possible when delivered. It is possible to store the material for a short period of time. Store it horizontally in a cool (6-8°C, 43-46°F) and dark place.
	Allow the mites in the tube to adjust to ambient temperature before use. Turn and shake the tube to mix the predatory mites equally in the vermiculite carrier.
	Remove the sticker on the screw cap and sprinkle the material on the leaves. Never sprinkle the mites by removing the cap (too many mites will be introduced on too few spots!).
	One tube is sufficient to sprinkle about 190 times. Each pile sprinkled consists of an average of 6-7 predatory mites. When necessary, the mites can be introduced a second time after 2-3 weeks. In hot spots, up to 20 Phytoseiulus/m² may be introduced.
	The predatory mites need a relative humidity of at least 65% and a temperature that regularly exceeds 20°C to develop well.

Note: Several pesticides have a negative effect on Phytoseiulus persimilis. Please be careful when controlling diseases and other pests. Consult Biobest's list of side-effects of pesticides on beneficial organisms.

In this system, the predatory mite Phytoseiulus persimilis is introduced with another carrier: saw dust (SD). This new carrier sticks better to the plants. Because of this, it is easier to apply the predatory mites in the correct quantity and place, even in the difficult dry and hot conditions the spider mite prefers.

The predatory mites are delivered in tubes of 2.000 adults with saw dust as carrier. The tubes are available in 250 ml and 500 ml. The larger the volume, the easier and more homogenously the predatory mites can be spread. This is especially relevant when introducing Phytoseiulus persimilis in large numbers or in the open field. Phyto-SD-System can be stored for a few days at 6-10°C and the relative humidity must be >85%.

	Saw dust sticks better to the plants
	Applicable in many crops
	Eats all spider mite stages
	Fast development
	Long-lasting protection
	Easy to handle and time-saving
	Ideal use in combination with Feltiella-System
	No waiting time

N.B. Several pesticides have a negative effect on Phytoseiulus persimilis. Please be careful when controlling diseases and other pests. Consult Biobest’s list on side-effects of pesticides on beneficial organisms.

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