Chemical Control Of Aphids In Greenhouse That Disallows Resistance

Due to their high reproduction capacity and resistance to numerous insecticides, aphids can be problematic pests in greenhouses.  As sucking insects, aphids damage greenhouse crops by causing curves and distortion of young, succulent stems. They may reduce the aesthetic quality and subsequent saleability of greenhouse crops in the presence of their shed skins and honeydew.  Unfortunately, aphids are often detected during flowering when it is most difficult to control them effectively.

The aphid is one of the most important types of insects found in greenhouses and can be identified by its large, thick, pear-shaped bodies.  Several species of aphids commonly occur, including the green peach aphid, Myzus persicae, and the melon or cotton aphid, Aphis gossypii.  The gray cabbage aphid is one you may encounter in a greenhouse environment, but on a plant of white flowers aphids are more commonly encountered. Proper identification is crucial to determining the most efficient management option. Aphids are commonly identified by their elongated abdomen and “tailpipes”, which are the cornicles. Cornicles are a useful guide to identifying aphid species.

As a greenhouse pest, aphids have the perfect storm to consider. They have a high reproduction rate, they prefer spring crops, they cause a lot of damage to plant health, and they are associated with a high rate of pesticide resistance. A further dilemma: Some growers may be pushed to avoid the use of a powerful tool, the neonicotinoids, due to this resistance. I offer a few suggestions concerning these obstacles.

Techniques and Tactics of Controlling Aphids In A Greenhouse

In greenhouses, chemical control and biological control can be used to manage aphids. However, aphids are difficult to control with insecticides for various reasons.  Poor strategies, inadequate coverage, or high pH in the spray tank may result in control failures. Different species of aphids will resist different insecticides.  Peach aphids tend to be particularly resistant to organophosphates, carbamates, and synthetic pyrethroids. Systemic treatments may perform better since the aphids feed on a lot of plant sap.  When plants are in bloom, covering the undersides of leaves is more difficult for contact sprays, and two applications of contact sprays may be necessary to gain full control. Additionally, many insecticides can cause spotting of blossoms, so they must be used with caution.

To create a more favorable environment for the introduction of natural enemies (predators, parasitoids, and pathogens), temperature and humidity can be manipulated. Before attempting biological control, make sure you are familiar with IPM scouting techniques and develop a regular monitoring program.  Release the natural enemy at the appropriate time when temperature and photoperiod are appropriate, as most control failures result because of environmental conditions when the natural enemy is released too late,  too slow a rate, or at the wrong time of the year.

Plants Attacked and Damage

Aphids feed by sucking in their stylet-like mouthparts into the phloem and digging out a mixture of sap and plant residue. Young leaves may become stunted, curled, and twisted as populations increase.  Black sooty molds can grow on honeydew, often reducing photosynthesis. Regular, weekly scouting is necessary to detect and treat aphids immediately after crops are in bloom. Yellow sticky cards will only attract successful insects.  Therefore, look for whitish-cast skins and honeydew on susceptible crops and cultivars to detect wingless nymphs.

It is essential to weed out heavily infested plants frequently and employ integrated pest management for aphid control on the rest. The hardest concept for many gardeners to comprehend is that “aphids are part of the garden ecosystem,” and attempting to eradicate them completely is futile. It would be more effective to consider ways in which aphid populations can be managed and controlled so that aphids do no harm and cause less annoyance.

How To Control Aphid: Using Chemicals and Others

There are a number of methods you may choose for controlling aphids once you have determined there are aphids present in your garden as well as determined whether you should take pest management action. In addition, cultural controls are included in Integrated Pest Management techniques, since they are primarily prevention-based and used to avoid an aphid problem in the first place. It is important to use cultural controls, including many methods of preventing aphid infestations, including proper irrigation, crop rotation, fertilization, selection of plant varieties, and proper plant spacing. The best management regimes often entail a combination of techniques that fall into one or more of these categories.

#1. Aphid-Control Pesticides

When you have a serious aphid problem in your garden, you may decide you need to use a pesticide. Avoid using broad-spectrum insecticides, as they will damage beneficial insects within the treated area, as well as pollute all plants.

#2. Homemade Aphid Spray

The recipe for the homemade aphid spray

  • Boil 1-gallon water in a deep saucepot
  • Add 3 tablespoons red pepper flakes to the boiling water, cover, and allow to boil for 15-20 minutes
  • Add chili flakes in the water for 24-36 hours, allowing the capsaicin in the chili to soak into the water (capsaicin, which causes nervous system damage to insects, killing them)
  • Strain the chili flakes from the mixture using a mesh pasta strainer or cheesecloth
  • Put the chili mixture in a storage container or sprayer
  • Add a few drops of Dr. Bronner’s peppermint soap – fatty acids in water can hurt insects with soft bodies.

If you are sick of aphids, you may use pepper/soap spray on your plants to avoid them from spreading. However, you must be careful to avoid touching your eyes when applying the spray.

Potential Consequences of Using Aphid-Control Pesticides

Pesticide use can lead to resistant aphid populations. This could only worsen the infestation as more aphids become pesticide-resistant. Some pesticides kill beneficial predator insects. Having a broad-spectrum pesticide can result in adverse reactions and damage to your plants, so it is counterproductive for aphid control. Certain chemicals can cause injury to your plants; always examine the label for limitations.

Some insecticides have the potential to be poisonous to both humans and pets. If they are exposed to certain chemicals, they can increase the risk of immediate illness and long-term effects in a developing fetus, such as birth defects or cancer. Aquatic plants and animals may be poisoned by-products applied near ponds and waterways.

Precautions to Take When Using Aphid-Control Pesticides

  • Do not use a dangerous product. Check the PRI’s Pest Smart website to assess whether a product must be used in your yard.
  • Apply sparingly to reduce harm to natural predators and avoid pesticide resistance.

Regulatory Update: Only use U.S. EPA approved products or exempt products that contain only “minimum risk” ingredients

Please read the label instructions and follow recommendations on the label, as they relate to the safety of the product and could make you liable for any damage resulting from not following these guidelines. 

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