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Whitefly Killer Cards - Encarsia formosa


Number of Cards

What Are Whiteflies?

Whitefly are sapsuckers of plants and can consume huge amounts of sap if they are left untreated. Much of this sap contains sugar and is excreted back onto plants by the Whitefly as honeydew, which sooty molds will grow on. Plant growth can be stunted, or slowed, when Whiteflies are present in large numbers. Leaves will also wilt or drop if the Whitefly remain present. Produce, such as Tomatoes, can be soiled and left with sticky deposits.

Whitefly can also transmit plant viruses from plant to plant. The most common Whitefly species that attacks indoor grown plants is the Glasshouse Whitefly (Trialeurodes vaporariorum), which Encarsia will treat.

What Are Encarsia Formosa Wasps & How Can They Help?

Encarsia formosa are natural parasites of Whitefly. These tiny Encarsia wasps have a yellow abdomen and a black upper body. Most of the Encarsia population are female and will lay eggs inside the Whitefly larvae which kills the pest and turns it into a parasitised mummy. This mummy is black in colour and will contain a developing Encarsia wasp.

The wasp grows, consuming the honeydew and body fluids of the parasitised larvae, before eating its way out by puncturing a small hole through the Whitefly mummy in order to emerge. The newly emerged Encarsia will then start to search for other Whitefly larvae to lay eggs in and kill. The wasps will leave black scale on the underside of leaves which will be evidence of the parasitised Whitefly scale of successful kills.

The Encarsia wasps have a very efficient flying pattern and will search plants for Whitefly. Once they locate the Whitefly larvae, they will stay in such an area until all the larvae have been parasitised for these hosts to feed on. This process is one of the oldest forms of biological control and has been used for many years, especially by tomato growers. It has a huge advantage over traditional chemical pesticide controls in that the Whitefly are unable to become resistant to attack by these tiny parasites

What Conditions Do Encarsia Require?

Temperature and day length will have a big impact on the activity levels of Encarsia. The Wasps will only fly in the day and low light levels will reduce their activity.

The Encarsia formosa are only fully active at temperatures of 17℃ plus. There may be minimal activity at lower temperatures but it will be slower and the Encarsia life cycle will take longer to develop. Temperatures above 17℃ will also, however, increase the activity and effectiveness of Encarisa. Even at higher temperatures the Encarsia life cycle remains quite long, though and it may take time before you see results, so some patience is required.  

The Encarsia formosa will develop more quickly than the Whitefly in optimum conditions however and will be able to easily establish control over Whitefly populations once they have become active.

Where Should I Apply Encarsia?

The Encarsia formosa are more effective if introduced in a controlled environment such as a greenhouse or glasshouse.

When Should I Apply Encarsia?

Introduce Whitefly Killer before Whitefly are in high numbers for best results.

How Do I Apply Encarsia?

First open your package carefully inside the area in which you wish to release them. Next bend and tear off the strips of the card, opposite the mounting hole, and suspend the cards on the plants you wish to treat for Whitefly infestation. This should be approximately 75cm under the plant head.

Ensure the cards avoid direct sunlight and do not directly touch the Encarsia pupae.

All the Encarsia will have emerged after a week, and most will have done so in the first few days, so each card can be removed and replaced after a week. More cards should be hung in areas of higher Whitefly activity.

How Many Encarsia Cards Do I Need?

Whitefly Killer Cards are supplied as a number of cards with tiny parasitised Whitefly pupae attached within them. We offer boxes containing cardboard strips of 5, 10, 25, 50 or 250 cards each. Approximately 60 Encarsia wasps will hatch per card. For large plants, such as tomatoes, cucumbers and large ornamental plants, we would recommend application of about 1 card per plant.

Can I Store Encarsia?

No. The eggs contained on the cards are primed and ready to hatch, therefore they can not be stored for use at a later date. The cards need to be applied as soon as possible after receipt.

Use Our Yellow Sticky Traps & SB Plant Invigorator If Conditions Do Not Permit Optimal Use Of Encarsia

If temperatures or light levels are low but Whitefly are still present, use our Yellow Sticky Traps and SB Plant Invigorator sprays on a regular basis until it is warm enough to introduce Whitefly Killer. These products ensure you can still achieve control over Whitefly populations and limit damage to your plants at any time of the year.

Consider Our Encarsia Card Programmes For Continual Control Over Whitefly

A programme of Encarsia introductions is the best way of achieving results from Whitefly Killer Encarsia Wasps. Professional growers, for instance, have found that introducing Encarsia in glasshouses with a programme of introductions is the most effective method of controlling Whitefly infestations.

A programme ensures populations of Encarsia are maintained to counter Whitefly populations when plants are vulnerable to attack, and helps ensure Encarsia are present as soon as the Whitefly appear. If there are already very high numbers of Whitefly present before Encarsia introductions have started, control of the pest can take a longer period of time. See our Encarsia formosa programmes here.

Chemical Pesticides

Encarsia Formosa is a living creature and can be affected by any chemical pesticides used within the previous few weeks. As a general guide, refrain from using Natural Pyrethrum or SB Plant Invigorator 2 days prior to use. Other chemical insecticides can have long lasting residues that could harm Encarsia Formosa and other predators for much longer periods. Refrain from using these products or check with Dragonfli for information on the effect of these products on our predators.

Customer Reviews

Based on 19 reviews
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Customer DR
Whitefly control

The Encarsia cards were hung and have reduced the whitefly numbers but not eliminated them ,so will order again to see how hungry the wasps are .

T
Thomas
Goodbye whitefly

Simple to use but need to be repeated

K
K.
Good control of whitefly in greenhouse

Great product, very effective. Timely delivery, but even so the minute encarsia were 'hatching' in the paperbag. Luckily I opened in the greenhouse, so none were wasted. I worried that I'd left it too late, as whitefly already quite noticeable, but after a few weeks, no sign of the little critters and their horrid sticky residue on my tomatoes.

E
Edward Bredenhann
Oops have l messed it up?

I am not sure what more l am supposed to do after l hung the cards onto plants? To date there has been no change- the cards are as l hung them?? Help please?

Hi Edward,

Many thanks for your feedback and for ordering with us.

It sounds as though you've applied them correctly, so please don't worry!

The Encarsia cards will not change, evidently, in appearance even after the wasps have hatched. The black dots will remain as they first appeared when applied as these are the shell casings that contain, or contained, the Encarsia.

If you look at them with a magnifying lens, you may be able to see cracks in the small shell casing that will indicate the Encarsia wasps have hatched.

On a further note, the Encarsia cards work best when introduced regularly over a number of weeks, enabling the parasite population to gradually increase, almost creating a little ecosystem within your respective glasshouse, greenhouse or polytunnel.

I hope this helps reassure you but if you need any further assistance please don't hesitate to get in touch again.

Kind regards,

Julian Ives [Director, Dragonfli]

M
Maurice Appleby
Very pleased

I have tried this treatment over the last couple of years and not once has it controlled the whitefly , however in response to my concerns the company have been very helpful and supportive and although I still have a whitefly problem in the greenhouse I think we, if not winning the battle, have at least started to see a decrease in their numbers. I would also add that there seems to be an increase in the amount of whitefly in the whole of the garden this year.