IPM: Aphid Control

Aphids are the most easily recognized pests in the greenhouse and yet my growers seem to struggle to find them until a small fire has broken out. I have certainly seen my share of aphids and even though we try to spray preventatively to control this pest, they pop up every year. So what are the best management practices for controlling aphids? It’s important to know what plants are most susceptible to aphids and were to look on the plant. Aphids tend to congregate on the tips of shoots and the undersides of leaves. It is also important to know the pest’s life cycle and biology. Below I will list my preferred control methods as well as the plants I find aphids on every year.

Preferred Chemical Controls:

• Marathon II (imidacloprid): This is my favorite for control of aphids. You can spray it on anything, anytime. I have used this product so many times and I have never seen any phytotoxicity, ever. I use it in tank mixes on a regular basis. Marathon II is also systemic meaning that if it is sprayed on the top of the leaf it will travel through the leaf to control pest on the underside. This is especially important for aphid control. Marathon can also be used effectively as a drench to systemically control aphids on pot plants and hanging baskets. We use it on all our susceptible hanging baskets and combos. It is best to use the wettable powder formulation (Marathon 60 WP) for drenching instead of the flowable Marathon II. Or you can topdress the granular Marathon.
• Endeavor (pymetrozine): This is a great chemical control for aphids as it is safer for workers and very easy on beneficials. Endeavor paralyzes the aphids mouthparts so that they can no longer feed on the plant. They eventually die from starvation. I’ve never seen phytoxicity and it tanks mixes well with other chemicals and it has a 4 hour REI.
• Talstar, Mavrik, Decathlon (pyrethroid): These are all pyrethroids that, in my experience, provide decent control of aphids. I usually tank mix them with and IGR (insect growth regulator) like Azatin, Distance, or Enstar. I often tank mix Avid with Talstar with decent results. These chemicals are ok for preventative sprays but if I need a quick knock down spray or I need to clean up a problem then I chose from the first two options.
• TriStar, Safari, Celero, Flagship (Other Neoniconitoids): These chemicals all have the same mode of action as Marathon but different active ingredients. It is important to employ a responsible rotation program when using neoniconitoids to eliminate the chance of resistance. Neoniconitoids are one of our most important chemical classes and should be used wisely to preserve it’s efficacy in the future.