Leptinotarsa decemlineata
Colorado potato beetles set such a grave menace to potato crop that flamethrowers have been used to control them . However , you do not have to go to such extremes in your garden .
We at Gardener ’s Path provide a number of natural control method acting to use against this voracious gadfly – and if necessary , pourboire on how to use insecticides as well .
Although not discover until 1811 , Colorado potato beetles quickly spread from the Rocky Mountains to the East Coast by 1874 , and make Europe a few years by and by .
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Left unchecked , these beetle can devour an full craw of white potato vine . And they also lay waste to these fruits and veg :
Infestations are so serious that they have even been considered part of international warfare !
In the 1950s , East Germanscalled these pests “ Yankee beetles”and accuse the United States politics of dropping them from planes during the Cold War . ( There was no evidence to support this claim . )
What You’ll Learn
Identification, Biology, and Distribution
Colorado potato beetles , aka potato hemipteran , are about 1/4 to 1/2 inch long . The country behind their heads is orange - yellow . you could easy identify them by the 10 alternating icteric and black stripes on their shells .
These voracious insects can be mix up with put on Solanum tuberosum beetles ( Leptinotarsa juncta ) , which are not plague . you may tell the departure because the fictive tater beetle have alternating white and black stripe on their shells .
Potato overhang larvae hatch from yellow - orange tree eggshell bunch on the bottom of leaves . fresh hatched larvae are bright red . The older orangish - pink larvae are about 1/2 inch long .
Larvae of all stage have dim head , and can be identified by the two row of blue dapple on each side of their humps .
These insects can be feel in every state except California , Nevada , Hawaii , and Alaska . They are also pests in every Canadian province , and in Central America . The beetles have spread to more than 6 million square knot across Europe and Asia .
Colorado Potato Beetle Life Cycle
Depending on the climate , these pests can survive through the wintertime as adult in gardens , domain gross profit margin , and windbreaks . In less favorable climates , the adults may winter in your stain .
The adult lay jaundiced to orange eggs about 1 mm long on the bottom of foliage , where they hatch into larvae .
The larva go through four growth stages ( instars ) , and the fourth instar larvae stimulate the most damage to intellectual nourishment crops . These hungry larvae are responsible for for up to 75 % of the damage to a harvest .
When the larvae complete this stage of their biography cycle , they drop to the ground and burrow several inches down before pupating .
pornographic mallet emerge 5 - 10 twenty-four hour period later , and depart feed and mating on their host plants . If conditions are not favorable , the adults may not emerge until spring .
A single female can lay over 500 orchis over a 4 to 5 - hebdomad period , and they can get on from larvae to adult beetle in 1.5 - 3 weeks , count on the climate .
Organic Control Methods
Once you have identified these worm pests in your garden , do n’t panic ! white potato industrial plant can mislay up to 30 % of their leaf and stems without any loss of issue .
Their most critical metre is after flowering , when the tuber have begin to bulk up . However , you will want to take activity before these demonic pestilence take over .
Your immediate reaction may be to reach for an insecticide . This may not be the best scheme , since Colorado murphy beetles are frequently resistant to pesticides .
Instead , your good bet is to look at a combination of dissimilar type of organic control condition method acting .
Physical Controls for Colorado Potato Beetles
If you are a home base gardener , one of the first and most effective things you’re able to do is to go on the offensive and pluck the slowly - incite mallet off your flora . This is easy to fulfill on a gay , warm day when the pests are out and about .
Just swing them into a container of buttery water supply ! That will dispense of these cruddy pests quickly and easily .
While it may be the most satisfying to kill the adult , make a gunpoint to get as many of the larvae as you could , as they cause the most damage . And do n’t blank out to crush any ball masses that you find on the bottom of the leave , which often appear around the same time that shoots are first emerging from the soil .
Be sure to put on gloves , and lave your hands afterwards . The bugs check a chemical that may irritate your skin .
float row coverscan help protect your plants from dirt ball infestations . Use a peculiarly designed lightweight be adrift wrangle cover and thoroughly secure the textile to the ground with grunge or staples .
guarantee that you are not covering plants in an arena where you farm them before . Since these cuss can overwinter in the soil , you could get an inadvertent infestation under the float row cover if you are not careful .
Another path to protect your works fromL. decemlineatais to grow plants that pull in these insect . If you grow bunker crops around the perimeter of your garden , the beetle will colonize the first emcee they see .
This can hold up their spread into your garden and give you a fortune to go on the offensive .
Potatoes are the most uncouth trap crops used forL. decemlineata . However , any host industrial plant that they enjoy munching on will process as a snare crop , let in other phallus of theSolanaceaefamily such asground cerise , horse nettle , tomato , and buffalo - bur .
commercial-grade tomato plant growers have had not bad success using white potato flora as trap crops . A Canadian testfound that Lycopersicon esculentum yields increased by 61 - 87 % using this approach .
you’re able to also grow non - host harvest like clavus in the country . This can confuse the beetles and delay infestation .
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Fittingly , you could habituate other type of insect ( or even spider ) to controlL. decemlineata . Somewell known beneficial insectsfor this aim include ladybugs ( aka lady doll beetles ) and gullible lacewing .
Normally thought of as a threat in their own right , several case of stinkbugsprey onL. decemlineata . These admit spin soldier and two - pick out foetor bugs .
Green Lacewing eggs , larvae , and adults are usable from ARBICO Organics
bloodsucking wasp are highly specialized for their hosts , andEdovum puttlerican help operate your plague . This wasp will lie its eggs in those of the beetles . Myiopharus doryphorae , a type of tachinid fly , parisitizes these pests as well .
You even have the option to expend microbic insecticides againstL. decemlineata . One eccentric of bioinsecticide containsBacillus thuringiensis var . tenebrionis(Bt - t ) bacteria .
This strain produce a toxin that aim the immature larva , so it should be lend oneself every few Day as soon as the orchis start up to hatch . If you give it too early , the bacteria wo n’t live until the larvae emerge , so the intervention wo n’t make for .
Bt - t is sensitive to UV rays , so you should spray late in the eve or on nebulose days . Also make trusted that it wo n’t rain within 8 hours after you have spray . you’re able to tell if the treatment is working because the larvae will grow black .
However , like other organisms , insects can acquire resistance to their attackers , and some Colorado white potato vine beetles expose resistance to Bt - t.
Another microbe that can be used to set on these garden gadfly is the fungusBeauveria bassiana , which can be used against both adults and larvae .
BotaniGard ® ES Beauveria bassiana spores via ARBICO organic fertiliser
aggregate this fungus with Bt - t can enhance the effectiveness of this case of restraint .
Several organic insect powder can aid to controlL. decemlineata . However , often when you spray an insect powder , you also kill the raw enemies of the pest you are assay to ensure .
One constitutive insect powder that is particularly good at killing these pests without slaughtering their born foe is spinosad . This compound acts best against vernal larval beetle , so you should apply it when you see the eggs think of .
Monterey Garden Insect Spray Concentrate ( spinosad ) via ARBICO Organics
You should spray neem crude in the evening , so it wo n’t impress beneficial insects . You will demand to reapply the neem oil frequently . It also acts most effectively against the immature larvae .
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Pyrethrins are another option to target the young larva . But keep in mind that these compound have a short half - life – only 12 - 13 minute .
PyGanic Gardening Pyrethrin in various sizes via ARBICO Organics
One of the master pyrethrin component almost altogether degrades after 5 years on tomato or white potato leaves , and someL. decemlineatapopulations have developed ohmic resistance against this grade of insecticides .
Cultural Controls for Colorado Potato Beetles
If you have had problem withL. decemlineatain the past tense , harvest rotation can be the most important ethnic dominance for this pestilence . This method stay plague and reduce the other season populations of beetles .
AJournal of Economic bugology studyof commercial potato fields on Long Island , New York , found that gyration with non - host plants like rye or wheat berry decreased the concentration of early time of year adult mallet by nearly 96 % . This effect wore off later in the season .
One thing you may do to enhance the success of crop gyration is to mulch with straw early in the time of year . This will make it even more hard for the beetles to find your crop .
Plus , it has an added incentive : this surround favour vulture of the mallet !
Rotating your potato or tomato plant crops every few age is a good strategy to reduce disease and beetle outbreaks . Many diseases are soilborne , and the mallet frequently winter in the soil .
go through a no - till system of rules ofcover cropshas been reported to help farmers greatly reduce their pesticide manipulation againstL. decemlineata .
There are several reasons why no - till works so well . One is that they can harbor the beneficial insect that serve as predators to the beetles . Another is that they discourage the pests from colonizing your plant .
You should considerplanting multiple types of cover cropslike buckwheat and Sudan eatage to pull different types of good insects .
Another strategy is to institute your covering crops sequentially , so they will flower at dissimilar multiplication . This will aid to increase the diversity of good insect uncommitted to round the potato beetles .
While you do want to pull the beetles if you are planting trap crop , this is not the case when you are develop cover crops tight to your potatoes or tomatoes .
With no - till practices , you should sanctify any alternative host like nightshade , solid ground cerise , jimsonweed , horse nettle , or black henbane that are growing in the area . This will forbid the mallet from feeding on these innkeeper plants and infect your crop after they come out of the ground in the springtime .
get a line more about no - till garden here .
Chemical Pesticide Control
Modern Irish potato growers often use chemical pesticides to control this pernicious pest . If the infestation in your plate garden is austere , you may need to consider this option .
A. Alyohkin and cobalt - authors claimed “ the Colorado potato mallet played a large role in creating the modernistic pesticide industriousness ” in a 2008 issue ofthe American Journal of Potato Research .
Your first thought might be to strain for a classical insecticide like Sevin ( carbaryl ) . However , you should hold off until you have consulted with your local county extension agent .
Colorado white potato beetle typically exhibit strong underground to such a pesticide due to its wide usage in the past . The population as a whole is resistant toat least 56 unlike insecticides .
However , no one mallet is immune toallinsecticides . Agricultural experts can tell you which 1 are potential to ferment in your area . Esfenvalerate may be one to assay .
Your good bet for chemical substance dominance is to spray after most of the nut have cover but before your plant are badly damaged . Take care that you apply these pesticidesin a safe mannerand follow all the instructions on the recording label .
You should rotate your insecticide use of goods and services among different classes , so the pest will not train underground .
Keep in head : it is likely that the natural method acting describe to curb these pests in your garden will be effective , without the demand for pesticide .
Go Forth and Garden
If you are faced with an attack of these undesirable visitor to the garden , you may start out by handpicking the matured pests and their larva , and oppress their egg masses .
instinctive control methods place from waging warfare with predatory insect and microbic insecticide to ethnic methods like using maw craw and implementing a no - till strategy . If necessary , you’re able to rely on the judicious usance of insecticides .
Gardener ’s Path provides a range of options for you to preserve your craw !
© call for the Experts , LLC . ALL right hand RESERVED.See our TOSfor more details . Originally published April 12th , 2019 . Last update April 22nd , 2023 . Uncredited photos : Shutterstock .
About
Helga George , PhD
