Pests

Pests that commonly attack Phalaenopsis (moth orchids) fall into two main categories: Insects and Mites. Successful treatment requires using the correct chemical agent for each:

• Insects require an insecticide.
• Mites require a miticide.

It is crucial to understand that insecticides will not kill mites, and miticides will not kill insects.

The two most common insect pests on Phalaenopsis are Scale and Mealybug. Fortunately, both of these insects are easily controlled.

Commercial growers typically use a two-part systemic approach:

1. Systemic Insecticide (e.g., Imidacloprid): This chemical is absorbed and travels throughout the plant's internal tissues. It kills adult and juvenile insects as they feed on the plant.
2. Insect Growth Regulator (IGR): This product is often trans-laminar (can pass through the leaf surface but is not fully systemic). Its purpose is to prevent emerging juveniles from maturing and reproducing, leading to a population collapse.

The two are applied simultaneously, typically diluted in a soapy water solution and sprayed directly on all plant surfaces. While the systemic product is highly effective against feeding insects, it often does not harm remaining eggs, which is where the IGR becomes essential for long-term control.

For professional growers, purchasing these insecticides is a standard practice, despite the requirements for a current Pesticide Applicator's License and the high cost of large containers.

However, home hobbyists with smaller collections often find this approach prohibitive. They are frequently frustrated by the ineffectiveness of "home remedies" such as soap, alcohol, and horticultural oil in controlling severe infestations.

A search for over-the-counter products containing Imidacloprid and an IGR revealed an interesting alternative: certain "Spot-On" flea treatments for large cats contain the exact same ingredients in the correct proportions. This led to an experiment to test their efficacy on orchids.

The research indicated that only Large Cat-specific flea treatments contained the necessary blend and proportion of insecticide/IGR. Products like Advantage 2 or Praventa for large cats were identified as suitable.

1. Each tube contains approximately 0.8ml of the pesticide blend dissolved in an alcohol/soap base.
2. One tube is sufficient to create a final volume of 500ml, enough to spray approximately 25 plants twice (seven days apart).
3. Carefully cut the narrow end of the plastic tube, keeping it pointed up to prevent spillage, as the liquid is very thin.
4. Add about 10 drops of liquid dish soap to 500ml of water.
5. Mix in the contents of one pesticide tube and shake well. 
6. Pour half of the mixture into a spray bottle. Note: A trigger-style sprayer is recommended over a pump-up style, as it atomizes the liquid better for superior coverage.

• For Mealybug infestations, it is helpful to use a kitchen sink sprayer to physically dislodge as many pests as possible before application.
• When applying the pesticide, spray both sides of the leaves, flower spikes, flowers, and the top of the growing medium for complete coverage.
• The unused spray remained effective for the second application one week later when stored in a cool, dark place.
• The spray was tested on Phalaenopsis and a tea plant, with no observed damage to either. Caution is advised when applying this solution to other orchid genera.
• The treatment performed as effectively as the commercial chemicals, and all treated plants were pest-free one month later.

If you choose to replicate this experiment, you must follow all precautions listed on the original product packaging. Wear appropriate personal protective equipment (PPE):

• Rubber gloves.
• A respirator with pesticide filters.
• Safety glasses.
• Clothes that are immediately washed after use.

Be fully informed of the risks before proceeding.