Greenhouse ornamentals-Mealybug


Citrus mealybug (Planoccoccus citri)
Longtailed mealybug (Pseudococcus longispinus)

Pest description and crop damage Like other soft-bodied, piercing mouthpart insects, mealybugs suck plant juices, cause tissue distortion, and plant decline, and secrete honeydew copiously. Keys are commercially available to distinguish species of mealybugs, scales, and whiteflies. Citrus mealybug, Planoccoccus citri, is a common pest in such situations. The longtailed mealybug, Pseudococcus longispinus is another familiar species in protected systems distinguished by two long waxy filaments forming a 'tail.'

Biology and life history Adult mealybugs lay their eggs generally in an ovisac or egg sack often near a stem juncture or under thick stipules. The ovisac is made out of a white, waxy secretion and may be filled with several hundred eggs. Once the eggs hatch, the tiny nymphs move around the plant where they feed. Adult female mealybugs resemble the nymphs, though larger, but the males look like small white-colored flies and are uncommonly seen.

Scouting and thresholds Scout for the white egg sacs near stem nodes and branch connections. Some species of mealybugs spend time as a root infesting aphid, so new plant acquisitions should be inspected for infestations above and below the plant surface.

Management-biological control

Natural enemies include:

  • lady beetle, Cryptolaemus montrouszieri, "mealybug destroyer"
  • predatory wasp, Leptomastix (for citrus mealybugs), Pseydaphycus angelicus (for longtailed mealybug),

Management-chemical control

Mealybug and scale pests are best controlled at the "crawler" stage: the immature, active stage when the insects are most sensitive to insecticides.

  • acephate (Precise, Orthene TR) at 0.024 lb ai/1,000 sq ft broadcast (0.6 oz). REI 24 hr.
  • acetamiprid (Tristar 30SG) at 0.5 lb ai/100 gal (2.7 oz). REI 12 hr.
  • afidopyropen (Ventigra) at 4.8 to 7.0 fl oz/100 gal.
  • azadiractin (Azahar, Azatin XL)-Some formulations are OMRI-listed for organic use.
  • Beauvaria bassiana (Botanigard, Mycotrol, Naturalis L)-Some formulations are OMRI-listed for organic use.
  • beta-cyfluthrin (Tempo Ultra) at 45 to 160 ml (1.5 to 5.4 fl oz) per 100 gal water.
  • bifenthrin (Talstar) at 0.168 to 0.335 lb ai/1,000 sq ft. REI 12 hr. Restricted use pesticide.
  • buprofezin (Talus 70DF) at 0.75 lb ai/a. REI 12 hr. Works on immature stage.
  • Burkholderia spp. (Venerate CG)-OMRI-listed.
  • canola oil (Captiva Prime) dilute 1 to 2 pints per acre; apply every 4-7 days.
  • capsaicin, garlic oil (Captiva) at 4 pints/a.
  • carbaryl (Drexel) 1 quart per acre or per 100 gal (0.75 fl oz per 1,000 sq ft).
  • chlorpyrifos (Quali-Pro Chlorpyrifos) at 0.5 lb ai/100 gal. REI 24 hr. RESTRICTED USE IN OREGON.
  • Chromobacterium (Grandevo)-Application rates based on host plant.
  • cinnamaldehyde (Seican)-Variable rates for first appearance, common and high pressure.
  • cinnamon oil (Cinnerate) at 13 to 64 fl oz/100 gal, 50 to 210 gal/a.clothianidin (Arena 0.25G) at 0.45 to 0.63 oz ai /100 gal. REI 12 hr. Soil treatment refer label.
  • cyclaniliprole/flonicamid (Pradia) at 10 to 17.5 fl oz/100 gal.
  • cyfluthrin (Decathlon) at 1.9 oz/100 gal. REI 12 hr.
  • cyfluthrin/imidacloprid (Discus L) at 0.063 lb ai/100 gal foliar; 0.009 to 0.014 lb ai/1,000 ft soil. REI 12 hr.
  • cyhalothrin (Declare) max rate at 0.12 lb ai/a.
  • DDVP (dichlorvos; Nuvan) 1.0% solution at 1 gal into 3.5 gal water.
  • deltamethrin (Deltaguard) at 2 to 3 lb/1,000 sq ft or 0.08 to 0.13 lb ai/a.
  • diazinon (Diazinon 50W) 1 lb/100 gal water; spray when first appear.
  • dimethoate (Dimate 4E)-Rate specific to host species.
  • 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.
  • esfenvalerate (Onslaught)- Apply full coverage foliar spray once every 7 days.
  • fenpropathrin (Tame 2.4EC) at 0.3 lb ai/a (16 fl oz). REI 24 hr.
  • fenproxymate (Akari 5SC) at 0.079 lb ai/100 gal. REI 12 hr.
  • flonicamid (Aria) at 0.067 to 0.134 lb ai/100 gal. REI 12 hr.
  • flupyradifurone (Altus) at 10.5 to 14 fl oz/a. REI 4 hr.geraniol, peppermint oil, rosemary oil (Keyplex Ecotrol) at 16 to 48 fl oz/100 gal; spray at first appearance, every 5-7 days.
  • 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)-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.
  • malathion (Malathion 8 Aquamul) at 1 pint in 100 gal of water as a dilute spray.
  • mineral oil/petroleum distillate (Biocover LS)-Some formulations are OMRI-listed for organic use.
  • naled (Dibrom 8)-Vapor treatment
  • permethrin (Bonide Eight)-Mix 1 fl oz in 1 gal water.
  • phenylethyl propionate (EcoPCO WP-X)-Water soluble pouches - 1 pouch/gal water
  • potassium laurate (several labels)-Some formulations are OMRI-listed for organic use.
  • pyrethrins/canola oil
  • pyrethrins/piperonyl butoxide
  • pyrifluquinazon (Rycar) at 0.09 lb ai/100 gal. REI 12 hr. Limit 2 treatments per crop.
  • pyriproxyfen (Distance) at 0.054 to 0.081 lb ai/100 gal (8 to 12 fl oz) foliar. REI 12 hr. Works on immature stages.
  • s-kinoprene (Enstar AQ) at 0.012 to 0.024 lb ai/10,000 sq ft. REI 4 hr.
  • sesame oil (Organocide) 1 quart/10 gal; spray early morning or evening. .
  • sodium borate (Prev-Am) at 50 fl oz/100 gal every 7-10 days.
  • soybean oil (Golden Pest Spray)-Some formulations are OMRI-listed for organic use.
  • spinetoram (XXPire) at 4 to 5.5 oz/a (0.05 to 0.069 lb ai/acre)
  • spirotetramat (Kontos) at 0.027 to 0.053 lb ai/100 gal. REI 24 hr. Systemic activity.
  • 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 14 to 32 fl oz/100 gal. REI 12 hr.
  • zeta-cypermethrin (Bug-No-More) at 15 fl oz per gal/1,000 sq ft.