Contents

Related

ohio

nature

places

Moths that migrate into Ohio

7 of the 9 on this chart are moving through Ohio today, 22 August.

  • Diamondback Mothsouthbound, at its peak now
  • Corn Earwormsouthbound, peaks 1 September
  • Beet Armywormsouthbound, peaks 1 September
  • Black Witchsouthbound, peaks 1 September
  • Fall Armywormsouthbound, peaks 5 September
  • Soybean Loopersouthbound, peaks 5 September
  • Cabbage Loopersouthbound, peaks 10 September

Due in the next fortnight

  • True Armywormfirst southbound moths about 25 August
  • Black Cutwormfirst southbound moths about 1 September
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Spring influx — the April arrivals Black Cutworm ↓Agrotis ipsilon · migrant · Breeds: Ohio corn seedlings, chickweed and winter annual weeds · Winters: the Gulf states and Mexico — no overwintering this far northOn territory in OhioSpring passage — peak Apr 20Fall passage — peak Sep 25 True Armyworm ↓Mythimna unipuncta · migrant · Breeds: grass, wheat, rye cover crops and early corn · Winters: the southern statesOn territory in OhioSpring passage — peak May 1Fall passage — peak Sep 20 Summer influx — the pest flights Corn Earworm ↓Helicoverpa zea · pest influx · Breeds: Ohio corn and soybean, in overlapping generations all summer · Winters: south of roughly the 40th parallel — not in OhioOn territory in OhioSpring passage — peak Jun 20Fall passage — peak Sep 1 Fall Armyworm ↓Spodoptera frugiperda · pest influx · Breeds: late Ohio corn, pasture and turf · Winters: south Texas and Florida onlyOn territory in OhioSpring passage — peak Jul 20Fall passage — peak Sep 5 Cabbage Looper ↓Trichoplusia ni · pest influx · Breeds: cabbage, broccoli and other brassicas in Ohio market gardens · Winters: the southern states and greenhousesOn territory in OhioSpring passage — peak Jun 25Fall passage — peak Sep 10 Soybean Looper ↓Chrysodeixis includens · pest influx · Breeds: late soybean, irregularly and only in warm years · Winters: the Gulf coast and FloridaSpring passage — peak Jul 25Fall passage — peak Sep 5 Beet Armyworm ↓Spodoptera exigua · pest influx · Breeds: vegetable crops and weeds, sporadically · Winters: the deep SouthSpring passage — peak Jul 20Fall passage — peak Sep 1 Diamondback Moth ↓Plutella xylostella · pest influx · Breeds: brassicas across Ohio, several generations a summer · Winters: the southern states — and it is not native to North America at allOn territory in OhioSpring passage — peak May 20Fall passage — peak Aug 25 Tropical strays Black Witch ↓Ascalapha odorata · stray · Breeds: not in Ohio · Winters: Mexico and the CaribbeanSpring passage — peak Jul 20Fall passage — peak Sep 1
NorthboundPresent in OhioSouthboundWintering in OhioToday↓ marks a species that winters off the bottom of the map. Hover a name for where it breeds and where it goes.

Almost every moth on this chart is an immigrant that arrived this year and will leave no descendants here — an Ohio winter kills them all. The populations are founded again from the south every spring, carried up on warm southerly airflows ahead of storm fronts, which is why the arrival dates move by weeks between years while a bird's move by days.

Why the moths left the butterfly chart

Split out of the butterfly chart because it answers a different question: not when to go and look at something, but whether this year's influx has landed.

Butterflies are a branch inside the moths, so the old "butterflies and moths" chart was never a division of equals. What forced the split was not taxonomy but audience: half the rows below are tracked by agricultural pheromone-trap networks because a spray decision hangs on the date of the first flight.

The three kinds, which are not the same thing
Kind What it means
migrant A northward push each spring from a permanent southern range, with a real southward return by a later generation
pest influx The same northward mechanism with an agricultural consequence, and little or no organised return
stray No population movement at all — individuals carried far outside their range, usually by a tropical storm

The rows on this chart
Species Northbound Southbound Winters
Black Cutworm 20 March – 25 May 1 September – 25 October the Gulf states and Mexico — no overwintering this far north
True Armyworm 1 April – 1 June 25 August – 15 October the southern states
Corn Earworm 20 May – 15 July 15 August – 1 October south of roughly the 40th parallel — not in Ohio
Fall Armyworm 20 June – 10 August 20 August – 5 October south Texas and Florida only
Cabbage Looper 25 May – 20 July 10 August – 10 October the southern states and greenhouses
Soybean Looper 1 July – 20 August 20 August – 1 October the Gulf coast and Florida
Beet Armyworm 25 June – 15 August 15 August – 30 September the deep South
Diamondback Moth 25 April – 20 June 1 August – 1 October the southern states — and it is not native to North America at all
Black Witch 1 July – 15 August 15 August – 1 October Mexico and the Caribbean

Where this sits

The butterflies are on Ohio butterfly migration, which is the chart these rows used to share.