Phytoline p Phytoseiulus persimilis

Spider control

Product description

Phytoline p is a proprietary product containing the proven predator Phytoseiulus persimilis (Athias-Henriot) , .

The product is available in 500cm³ and 215cm³ bottles containing 2000 for application over wide areas, and also in 30 cm³ vials containing the same number of mites for treatment of ‘hot spots’

The 125cm³ and 30cm³ are available with either vermiculite or sawdust as the carrier material. The sawdust adheres better to leaves when first applied, and is preferred for crops with small, glossy leaves. The 30cm³ vials are supplied with a re-closeable flip-top for accurate spot applications. 125ml bottle formulations can be used with mite application machinery. How does it work?

Phytoseiulus persimilis is an active predatory mite that has specialised in feeding on mites in the family Tetranychidae. This includes the common Red Spider Mite or Two-Spotted Mite , and the Carmine Mite Tetranychus cinnabarinus. It is also reported to feed on some species of Oligonychus, but it is unable to feed on other prey or pollen. In the absence of spider mites it cannot become established.

Female P.persimilis lay eggs amongst colonies of spider mites. The egg hatches to produce a six legged larva, which does not need to feed, and this is followed by protonymphal and deutonymphal stages. These two stages and the adult that follows feed voraciously on all stages of the spider mite, although they may show a preference for eggs. They are adapted to move easily over and amongst the webbing produced by the spider mites. Research has shown that they are attracted to leaves damaged by spider mite attack from some distance away. They may also be attracted by spider mite webbing.

Phytoseiulus persimilis was one of the first beneficial to be commercialised, following successful trials for the control of acaricide-resistant spider mites on cucumber crops in England.

At 20°C, eggs hatch in just over 3 days and development is completed within 10 days. This compares very favourably with the development of Tetranychus urticae, which takes nearly 17 days to complete its development at the same temperature. Once a female reaches adulthood, it may be a few days before she is able to lay eggs,

but once she starts an average female will lay 2-4 eggs per day and may lay more than 50 eggs during her lifetime.

At 30°C, the total development time is reduced to 5 days, which again compares favourably with a development time of 7.3 days for Tetranychus at the same temperature. There are approximately four females to every male of P. persimilis, so that the majority of individuals supplied are capable of laying eggs and the population can grow very rapidly. Commercial products may contain a higher proportion of females, but these will have mated during the production process and will be ready to lay eggs when released into colonies of spider mite.

INSTRUCTIONS FOR USE OF Phytoline p. Phytoseiulus persimilis

• Keep vials/ bottles horizontal and cool until use. DO NOT expose to direct sunlight at any time. • Immediately before opening, tap the base of the vial/ bottle sharply on a solid surface to dislodge the mites from the inner surface, and gently roll the vial/ bottle to distribute them evenly throughout the carrier material.

VIALS • Open each vial in the glasshouse when ready to use it. • Apply the mites by inverting and tapping the vial over the spider mite infested leaves. • Before closing the re-closeable vial, tap it sharply to dislodge mites from the cap. Tap and roll the vial before re-opening it. • Leave the empty vial and lid on infested plants to allow any remaining predators to escape BOTTLES • Distribute the product over the leaves, gently shaking and rotating the bottles to give uniform distribution. Vigorous shaking will kill the mites. • Apply at an rate of 4/m². Repeat the introduction and increase the rate in established spider mite colonies until control is achieved. STORAGE • Use within 18 hours of receipt. • Keep in darkness at 5°C - 10°C with the vials horizontal until use.

When and where should you use it?

Best results are obtained by releasing Phytoseiulus persimilis soon after spider mites first appear on the crop. This may occur during the spring in field crops, when conditions are suitable for diapause break. In protected crops spider mites may enter diapause in September, but can become active again at any time from early January. In continuously heated crops, or where artificial light is used to extend the day length, the spider mites may remain active all year.

Phytoseiulus persimilis may be used on any crop where spider mites are a pest. It is used widely on field grown and protected strawberries, on protected salad vegetables such as cucumbers, peppers, tomatoes and aubergines, and increasingly on ornamental crops such as roses.

In salad vegetables there is some tolerance of leaf damage, so a balance is sought between pest and predator populations, as exemplified by the ‘pest in first’ strategy developed by the Glasshouse Crops Research Institute in England. In ornamental crops rates may be higher, or releases may be made on a much more frequent basis. The low or zero tolerance of damage on these crops means that a preventive programme is preferred, where predators are released whether prey is present or not. Hungry predators search the crop thoroughly and find small numbers of spider mite before they are able to establish and cause visible damage.

How should you use it?

Phytoseiulus persimilis is supplied as units of 2,000 in 500 cm³ or 125cm³ bottles, or 30 cm³ vials, with vermiculite or sawdust as a carrier material. In all cases it is essential to ensure that the mites are evenly distributed throughout the carrier before removing the cap to apply them. On receiving the bottles or vials, make sure they are kept horizontal and cool until use. Immediately before use, tap the container sharply on a hard surface to dislodge the mites from the inner surface. Roll the container gently to distribute the mites evenly in the carrier material before opening it. To release the mites, tap the container gently with a finger, while holding it horizontally above the infested foliage. Continue to roll the container while tapping it, to maintain uniform distribution of mites in the carrier material.

Use the 500 cm³ unit size to achieve wide distribution of the mites over lightly infested areas or in low growing crops, for example in strawberries. For more accurate application of mites to leaves, use the 30cm³ unit. Each tap of this unit releases 5-10 mites and the smaller volume means that the mites are less likely to fall from the leaf with the carrier material. This unit is particularly useful for releasing mites into crops such as tomatoes, where heavy, localised spider mite outbreaks can occur. On crops where the plant leaves are small and glossy, a vermiculite carrier will tend to fall to the ground quickly: sawdust is preferred as a carrier material because it adheres to the leaves for longer.

125ml bottle formulations can be used with mite application machinery.

Phytoseiulus should also be released into the areas around the outbreaks. If this is not done, the predators may remain in areas of plentiful food and not migrate to the edge of an infestation. Surviving spider mites at the periphery then continue to breed unchecked and the colony may expand in a ring away from the areas containing predators.

When should you not use it?

Phytoseiulus persimilis performs best in warm, relatively humid, conditions and may fail in hot, dry conditions, such as along the south side of some glasshouses, where the low humidity favours the spider mite. In these conditions, it is better to use the alternative predators Amblyseius andersoni, Amblyseius californicus or a combination of the two species. Although laboratory studies seem to show that A. californicus is no more tolerant of low humidity than P. persimilis, it has nevertheless proven more effective in these conditions in the field.

Many growers experience difficulty in controlling spider mite outbreaks on tomato crops. Some commercial suppliers produce a ‘tomato-conditioned’ strain, but independent research has shown that this had no advantage over normal fresh stock despite the higher cost. In general, early release at high rates onto and around identified spider mite colonies remains the best option, with spot applications of compatible acaricides being used to treat larger outbreaks.

The predatory midge Feltiella acarisuga can also be useful for control of spider mite. It frequently invades crops naturally, but inoculative releases ensure that it is present.

Where Macrolophus caliginosus is established it will contribute to spider mite control on tomatoes and aubergines, but will prey on other beneficials such as Feltiella.

What will it do?

When used as advised, Phytoseiulus persimilis will control spider mites on the majority of protected crops. Success on outdoor crops is dependent on weather conditions at the time of application, and subsequently.

What will it not do, and what are the control options?

Phytoseiulus persimilis will not control the European Red Mite, Panonychus ulmi, nor Broad Mites (Tarsonemidae) or Rust Mites (Eriophyidae). Neither will it control very large populations of spider mites at normal introduction rates. Existing damage to leaves will remain even when all spider mites have been cleared from the area, so on crops where damage thresholds are low it must be used preventively. For control of these other pest mites Amblyseius andersoni and A montdorensis should be considered.

Chemical compatibility Fumigation with sulphur on a regular basis can prevent establishment. One possible mechanism for this is a prevention of mate finding or host finding by adults.