Flea Beetle

flea-beetleBiological information:

  • Common name: Flea Beetle
  • Scientific name: Alticini spp., Phyllotreta spp., Podagrica spp.   
  • Family or class: Chrysomelidae

Symptoms and/or signs to watch out for:

  • Presence of adult beetles on leaves
  • Flea Beetles damage plants by chewing small holes in the foliage
  • Watch for sudden burst of jumping black spots among leaves

Life cycle:

  • Overwinter in the adult stage
  • Become active during warm days in mid-spring
  • Seek out host plants by locating chemical sues that some plant produce
  • Adults feed for several weeks
  • Soon females intersperse feeding with egg laying
  • Lay eggs in soil cracks around the base of the plants
  • Worm-like larvae move to feed on small roots and root hairs
  • Larval stage is completed in a month
  • Pupate in the soil for 2-3 weeks and emerge as adults
  • May be more than one generation per year

Mode of reproduction:

  • The flea beetle reproduces by sexual reproduction

Vectors for the pest:

  • Potato flea beetle spreads spindle tuber blight, brown rot, and potato scab
  • Corn Flea Beetle spreads Stewart’s bacterial wilt of corn

Overwintering habit:

  • Adult flea beetles overwinter in the leaves or fallen foliage that they use as protection

Alternate hosts:

  • May have been seen at UNH on mesclun mix
  • Brassica foliage
  • Potato tubers and foliage
  • Solanaceous crops

Horticultural production information:

Preventative strategies:

  • Crop rotation – avoid planting crops prone to flea beetles in the same area over different seasons and in consecutive years
  • Soil disruption in late fall

Threshold levels:

  • Economic threshold level is when greater than 25% of the foliage is affected

Control options:

Physical controls:

  • Plant earlier or later in the season to avoid peak larvae feeding times
  • A good option for Brassica crops is to plant in mid to late July, reducing areas where overwintered flea beetles can feed and reproduce
  • Use trap crops to lure flea beetles away from cash crops (ex: Chinese Southern Giant Mustard)

Biological controls:

  • Entomopathogenic Nematodes- soil-dwelling parasitic worms that kill insects
  • Steinernematidae and Heterorhabditidae families can attack larval stage of flea beetles

Chemical controls:

Kaolin (Surround WPOG):

  • 12.5 to 50 lbs/A or 0.125 to 0.5 lbs/gal (0 dh, REI 4h, Bee:L)
  • This is for suppression and repellence only
  • May be applied to transplants prior to setting in field
  • Use on seedlings and young plants
  • Product residue may need to be washed off if applied after fruit set
  • White residue may be minimized if applications stop when fruit is 25% of its expected harvest size
  • Generally compatible as a tank mix with other insecticides

Petroleum Oil (Suffoil XOG):

  • 1 to 2 gal/100 gal water (0 dh, REI 4h, Bee:L)
  • Apply as needed
  • Beetle larvae only

Pyrethrin (PyGanic EC5.0OG):

  • 4.5 to 18 oz/A or 0.25 to 0.50 oz/gal (0 dh, REI 4h, Bee:L)
  • For field and greenhouse use

 

Historical notes from Farm to YoU NH:

Date/circumstances observed (Pictures)

Control method used, efficacy of control method

 

References:

http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/insects/beetles/flea-beetle.aspx

https://www.uvm.edu/pss/ppp/pubs/el71.htm

 

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