Pest description and crop damage Aphids are soft-bodied insects with piercing-sucking mouthparts. They are usually identified by host plant, and characters such as wing venation, antennae, and cornicals. The same species can vary in color, shape, and size depending on the time of the year. Crop damage includes distorted plant growth, particularly terminals, shiny honeydew, black sooty mold (which can grow on the honeydew), waxy deposits (some species), yellowing, and general plant decline.
Biology and life history There are winged (alate) aphids which can migrate, and wingless adult aphids which remain on the host but can reproduce asexually, producing large aphid populations quickly. Most aphids are associated with one or several host plants. Some have alternate hosts, overwintering on one host and moving to another as the season progresses. Several species, including many common in greenhouses, have a wide host range, with many host plants including weed species. Examples of these species include: green peach aphid (Myzus persicae), cotton or melon aphid (Aphis gossipea), potato aphid (Macrosiphum euphorbiae), and cabbage aphids (Brevicoryne brassacae).
Scouting and thresholds Scout for aphids near growing terminals and leaf undersides, particularly alongside leaf veins. White cast skins, shiny honeydew, black sooty mold, and misshapen terminals are good indicators of aphid presence. Yellow sticky traps and yellow pan traps can help monitor flights of adults.
Natural enemies include:
- hover flies, many species-Maggot-like larvae are voracious predators of aphids. Pollen and nectar feeding adults are commonly seen around flowers.
- lacewings (Chrysopa spp., Chrysoperla carnea, C. rufilabris, C. comanche)-Some species commercially available.
- lady beetles (Hippodamia convergens, Harmonia axyridis, Coleomegilla maculate, Coccinella septempunctata)-Note: Use of non-local, wild-harvested lady beetles is discouraged due to potential movement of lady beetle pathogens and parasites.
- pirate bugs (Orius spp.)-Some species commercially available. Both adults and larvae are predators of small eggs, insects, and mites.
- parasitoid wasps (Aphidius ervi, A. matricariae, A. colemani, Aphelinus abdominalis, Diaeretiella rapae, Lysiphlebus testaceipes, Trioxys pallidus)-Some species commercially available. Many parasitoids have preferred hosts. See specific aphid for more information.
- predatory midge (Aphidoletes aphidimyza)-Commercially available and has given good control. Maggot-like larvae are voracious predators of aphids. Adults may go into diapause with low light or short days.
Good spray coverage, including the underside of leaves, is important. Aphids excrete honeydew which attracts ants. Ants may need to be controlled by an underbench treatment before releasing biological control agents.
- abamectin (Avid 0.15EC) at 0.009 lb ai/100 gal (8 fl oz). REI 12 hr. For suppression only.
- acephate (Precise, Orthene TR) at 0.024 lb ai/1,000 sq ft broadcast (0.6 oz). REI 24 hr.
- acetamiprid (Tristar 30SG) at 0.24 lb ai/100 gal (1.3 oz). REI 12 hr.
- azadirachtin (Azahar, Azatin XL)-Insect growth regulator, antifeedent. Some formulations are OMRI-listed for organic use.
- Beauvaria bassiana (Botanigard, Mycotrol, Naturalis L)-Works by contact, good coverage required. Some formulations are OMRI-listed for organic use.
- bifenthrin (Talstar) at 0.084 to 0.168 lb ai/1,000 sq ft. REI 12 hr. Restricted use pesticide.
- canola oil (various RTU products)-Good contact is essential. Some formulations are OMRI-listed for organic use.
- chlorpyrifos (Quali-Pro Chlorpyrifos) at 0.25 to 0.5 lb ai/100 gal. REI 24 hr. Restricted use pesticide.
- clarified hydrophobic extract of neem oil (Triact 70)
- clothianidin (Arena 0.25G) at 0.315 to 0.63 oz ai/100 gal. REI 12 hr. Soil treatment refer label.
- cyantraniliprole (Mainspring) at 0.16 lb ai/100 gal drench. REI 4 hr.
- cyfluthrin (Decathlon) at 1.9 oz/100 gal. REI 12 hr.
- cyfluthrin/imidacloprid (Discus N/G) at 0.063 lb ai/100 gal foliar; 0.009 to 0.014 lb ai/1,000 ft soil. REI 12 hr.
- dinotefuran (Safari 20SG) at 0.1 to 0.2 lb ai/1,000 ft sq; 0.05 to 0.1 lb ai/100 gal. REI 12 hr.
- flonicamid (Aria) at 0.022 to 0.067 lb ai/100 gal. REI 12 hr.
- flupyradifurone (Altus) at 7.0 to 10.5 fl oz/a. REI 4 hr.
- garlic oil/powder (Allityn Insect Repellent)-Some formulations are OMRI-listed for organic use.
- imidacloprid (Marathon II) at 0.027 oz ai/100 gal foliar. REI 12 hr. Drench and irrigation permitted.
- Isaria fumosoroseus (PFR 97) at 0.175 to 3.5 lb ai/100 gal foliar. REI 4 hr.
- kaolin (Surround) may leave residue-Some formulations are OMRI-listed for organic use.
- lambda-cyhalothrin (Scimitar GC) at 0.013 to 0.043 lb ai/100 gal. REI 24 hr.
- methiocarb (Mesurol 75W) at 0.375 to 0.5 lb ai/100 gal. REI 12 hr. Restricted use pesticide.
- mineral oil/petroleum distillate (Biocover LS)
- naled (Dibrom 8) as vapor treatment.
- pymetrozine (Endeavor) at 1.25 to 2.5 oz ai/100 gal. REI 12 hr.
- pyrethrins (E.B. Stone, Earth-tone, Worryfree)-Good contact essential. Some formulations are OMRI-listed for organic use.
- pyrethrum/piperonyl butoxide-Synergist increases toxicity to insects.
- pyrifluquinazon (Rycar) at 0.034 to 0.045 lb ai/100 gal. REI 12 hr. Limit 2 treatments per crop.
- pyriproxifen (Distance) at 0.041 to 0.054 lb ai/100 gal (6 to 8 fl oz) foliar. REI 12 hr. Suppression
- s-kinoprene (Enstar AQ) at 0.012 to 0.024 lb ai/10,000 sq ft. REI 4 hr.
- spirotetramat (Kontos) at 0.027 to 0.053 lb ai/100 gal. REI 24 hr.
- tau-fluvalinate (Mavrik Aquaflow) at 0.063 to 0.156 lb ai/100 gal. REI 12 hr.
- thiamethoxam (Flagship 25WG) as fogger. REI 12 or 24 hr.
- tolfenpyrad (Hachi-Hachi) at 0.14 to 0.33 lb ai/100 gal. REI 12 hr.