4 European corn borer egg mass at the blackhead Fig. Another type of damage is ear drop where cobs fall to the ground. Its host rangehas more than 200 species of plants, including both agronomic and horticultural crops and many common weeds. This non-Bt corn will act as a refuge for some of the corn borers, thus preserving the genetic diversity that is now in the corn borer population. In regions where only one generation occurs, the larvae will stay in diapause throughout the winter. The European corn borer, an introduced species, has been an important pest of corn in the Midwest since the 1920's. The eggs hatch in three to nine days depen d-ing upon weather conditions. Once the black head is visible, hatching is imminent. The European corn borer will feed on sweet, grain and silage corn. Depending upon how many generations occur within a specific region, the fifth instar will do one of two things. Control of the damaging larval stage is imperative, but egg and adult moth control should not be overlooked. At the first instar the larvae are white in color with a black head and are approximately 1/16 inch long. Each cluster can have as much as 30 eggs. The borer is representative of the larva stage (Fig. Check with your local extension personnel, as to when it is necessary to start sampling. Start checking for egg masses in corn when corn borer moths are being collected in light or pheromone traps. The stage that damages crop plants is the larvae, but it is the adult moths that are attracted to and captured in traps. Eggs are likely deposited on the underside of hop leaves in masses of 20 to 30 and covered with a waxy film. A historical perspective The European corn borer (ECB) was most likely introduced into the US in the early 1900s and into Minnesota in the 1940s. European Corn Borer. The European corn borer (Ostrinia nubilalis), also known as the European corn worm or European high-flyer, is a moth of the family Crambidae which includes other grass moths. For non-Bt corn, look on the undersides of leaves for corn borer egg masses. Fig. To see an animation illustrating the entire lifecycle of the ECB, click on the Life cycle animation above. It is one of the major economic corn pests in Illinois. Newly hatched larvae typically move from the leaves to protected areas of the leaf axils and sheaths to feed on pollen and plant tissue. Approximately 90% of the egg masses will be found on these middle seven leaves. Native predators and parasites exert some effect on European corn borer populations, but imported parasitoids seem to be more important. During the second instar, the ECB grows larger and becomes more yellow in color. This eliminates the need for the application of a corn borer insecticide. In most of Wisconsin, two generations of eggs are laid on the undersides of leaves. Preventable yield loss (bu/A) = anticipated yield (bu/A) X yield loss figure (from following table) X level of infestation (decimal) X anticipated level of control (decimal). Anticipated yield is 150 bu/A and the crop is valued at $2.75 per bushel. European Corn Borers are a voracious pest of corn, potatoes and many other commercial crops causing large-scale yield loss. Compare preventable dollar loss/A to cost of insecticide and application to determine if treatment is warranted. Pull out, carefully unroll, and examine the whorl leaves from one plant showing damage in each sample set, for a maximum of 5 plants in the field. The pupa stays inside the corn stalk and later emerges as a moth in July and August to start the second generation. This step is necessary for the adult moth to form. European corn borer eggs are laid in masses of 15 to 30 eggs per mass. 1997). Buff-colored moths begin to emerge in early June and deposit eggs in masses on the underside of leaves. Prior to the widespread adoption of effective Bt, Minnesota ECB populations went through cyclical fluctuations caused by disease. Age of the egg mass is indicated by its color: freshly laid eggs are white, then cream. Female corn borer moths lay clusters of eggs on corn leaves, usually on the underside of the leaf. European Corn Borer. The European corn borer causes damage in several ways. Purdue University is an equal access/equal opportunity university. Throughout these five instars the larva are growing and preparing to become adults. European corn borer egg masses will appear as a small white area of overlapping scales. Other Midwestern states have reportedly experienced more substantial damage from this introduced moth. Or it may cause corn to become stunted, resulting in yield reductions caused by the inability of the plant to transport water and nutrients through its damaged stalk. European Corn Borer Egg Masses European corn borer egg masses […] 4 ECB blackhead egg mass: This picture shows the egg mass in the blackhead stage, prior to the larvae emerging. The mature larva is about 1 inch (25 mm) long, creamy to grayish in color, and marked by rather inconspicuous rows of small, round, brown spots running the length of its body. European corn borer (ECB Ostrinia nubilalis Hübner) is a pest that invades over 200 species of plants. European Corn Borer, Ostrinia nubilalis. European corn borer eggs are laid in masses of 15 to 30. Other known corn borer control methods include using garden insect sprays to kill young caterpillars. First Generation. 1995). Larvae may bore into the ears where they feed on the kernels and cob, resulting in yield losses, as well as avenues for attack from secondary insects and pathogens (e.g., ear rots). European corn borers pass the winter as full-grown larvae in corn stalks, corn cobs, weed stems, or in other cornfield debris. Later look carefully into the whorl for developing larvae. Together, these four different stages of development make up one generation. However, the second instar creates larger holes than the first. European corn borer eggs are smaller than the head of a pin but are laid in visible groupings. Other above and below ground insects may be present during the season and Bt corn provides little to no protection against these. Egg-laying for the second generation is generally heaviest in silking-stage corn during the July to August moth flight. European Corn Borer. The eggs of European corn borer appear in masses, with each having an average of length of 1/8 to 3/16 inches. Female moths generally lay their eggs on the underside of corn leaves (often along the leaf midrib), leaf sheaths, and/or ears, depending on the generation, in masses of 15 to 30 eggs overlapping like scales of a fish. ).The European corn borer passes the winter as full-grown larva in corn stalks … If these refuge are not included in plantings of Bt corn, the technology may be short lived or seed companies will constantly have to introduce new genes, if available, or stack genes to combat this situation. The number of actual larvae observed averages 2 per plant. $14.76/A (preventable $ loss/A) - $10.00/A (cost of control) = $4.76/A return from application of control. The European corn borer can be found in areas east of the Rocky Mountains from the Gulf Coast to southern Canada. Overwintering larvae pupate in the spring, emerging as moths in late May and early June. At the fifth instar, the larvae are approximately one inch in length. Fig. The location of egg masses of the European corn borer, Ostrinia nubilalis, was studied on potatoes {Solanum tuberosum) "Russet Burbank' grown on Prince Edward Island, Canada, from 1990 to 1992. Distribution. (1993) found that 89% of the masses were found on the four leaves just below the ear of field corn. 1971). Kill European corn borer (ECB) before it tunnels into tassels, stalks and ears. 'The eggs are laid in masses on the underside of corn leaves near the midvein' (Michigan State University, 1997). For control tests (including two plants sprayed with ultrapure water), females laid similar numbers of eggs on each plant (plant a=167±38.3; plant b=166.6±57.6 eggs), and they only laid eggs on leaves 4 to 7 with a higher number of eggs on leaves 4, 5, and 6 ( Fig. When this flight winds down, the bivoltine. provides maize growers with a warning of the threat of the European Corn Borer. 4). As the corn plant reaches maturity the tassel emerges from the whorl of the plant thus eliminating second generation larval feeding on this part of the plant. Approximately 90% of the egg masses will be found on these middle seven leaves. The original European corn borers introduced to North America in the early 20th century established a population in New York. Unfortunately, damaging levels of European corn borer (ECB) larva e are present in some Michigan hopyards this year. Incorrect: The larval stage of ECB is the most damaging to crops because this is when the most feeding and growth occurs. The cost of the insecticide and application is $12.00 and 65% control can be expected. As the borers feed on the leaves, they typically produce a characteristic random or "shot hole" damage pattern. Corn Insect Control Recommendations: E-series 219-W (PDF). Second generation borer attack may result in stalk or tassel breakage and/or boring into the ear shanks, which may cause ears to drop off. 7b). General. Inside each Tricho-Corn card, there are 8000 Trichogramma pupae of Trichogramma ostriniae. The fourth and fifth instars feed only on the stalk. If you do find signs of corn borer activity, sample to ascertain the extent of infestation. Moths may be “flushed up” by walking through the field. Although, European corn borer egg masses were collected each spring following summers of release, no T. ostriniae have been recovered thus far in New York, indicating that it does not overwinter. They hatch into pale brown moths with zigzag markings in June. European corn borer egg masses go through several stages of development. After the last generation for a region, the ECB will go into diapause for the winter. Egg masses These develop in the same manner as the previous generations. Several beneficial insects find corn borer eggs a delicacy, including ladybugs and lacewings. 3 ECB egg mass: This picture shows the egg mass after being laid near the midvein of the corn leaf. They start as white but as they mature and when they are about to hatch, they become cream. The European corn borer, an introduced species, has been an important pest of corn in the Midwest since the 1920's. 1995), Fig. European corn borer (Ostrinia nubilalis) has been a minor pest of hop in Michigan over the last decade. If European corn borer moths are active (e.g., pheromone trap captures >7 per week) and laying eggs during the period when ears are forming, an additional spray during silking can help reduce the number of small borers that move directly into the ear after hatching. SWCB and ECB lay eggs in an overlapping pattern that look like small fish scales. The egg masses have a scaly, glossy white appearance (Figure 1). 'The eggs are laid in masses on the underside of corn leaves near the midvein' (Michigan State University, 1997). 5). The moths will begin to emerge from diapause and begin mating. For 1/4 egg mass/plant, an average of 1 borer would survive per plant (assuming survival of 4 borers/egg mass). European corn borer (ECB) is the most serious annual pest of peppers in New Jersey. THE EUROPEAN CORN borer, Ostrinia nubilalis (Hübner), tends to oviposit within certain regions on the corn plant. European Corn Borer About European Corn Borer European Corn Borers, Ostrinia nubilalis, are a pest of corn. Late instar larva. After undergoing several molts, the larvae bore into the corn plant as did the first generation borers. The first sign of damage is the pinhole damage. In general, it is suggested that at least 20% of the acreage in an area be grown in non-Bt corn. SWCB egg masses are usually smaller (2-8 eggs) than those of ECB (10 or more eggs). The female moth will begin laying eggs in June, after sunset when the wind is calm and the temperature is warm. However, the fifth instar must be present in the corn stalk or plant debris in order for diapause to occur after the final generation. Egg masses, which will produce second generation borers, are laid in corn during late July and throughout August. 1) and the ECB moth is representative of the adult (Fig. 2 ECB: Adult female moth (Jim Kalisch, University of Nebraska Lincoln. The diapaused larvae form a brown capsule-like cocoon, the pupa (Fig. Often, second generation egg laying may extend to 21 days or more. © Copyright Plant and Soil Sciences eLibrary 2021. European Corn Borer larvae are dirty white in color and may change to a light tan or pinkish gray as they mature. Since most of the eggs are laid in the middle third of the plant, check the ear leaf and the leaves at 2 nodes above and 2 nodes below the primary ear. First Generation - Early planted corn is most likely to develop problems with first generation borers because moths are attracted to the tallest, greenest corn for egg laying. Avia… The third instar begins feeding on the outside before boring into the stalk and creating cavities in the plant. In the first field trials with T. ostriniae in the USA, Mason et al. For young corn plants, inspect leaves for eggs masses. Second Generation - Use the following steps to determine whether treatment is economically justified: Example: A field that is shedding pollen has 60% of the plants infested with larvae and/or egg masses. The economic threshold for European corn borer egg masses: Average of 1 egg mass per 15 plants. Total the number of plants showing such damage to determine the percentage of damaged plants. During late July and early August adults mate in grassy areas (e.g., roadsides, waterways, weed patches, etc.). The white, flat eggs overlap each other like fish scales and are laid in masses of five to 40 eggs. Second generation borers normally concentrate their attack in the ear zone, roughly the middle third of the plant. The European corn borer (Ostrinia nubilalis), is a severe pest of maize and has also been reported to attack apple, strawberries, peppers and other plants.It is present in Europe, North Africa and North America, where it was introduced. First generation borers are usually present during June in the whorl of corn plants. This miniature (less than 0.5 m in length) insect will parasitize and kill the entire ECB egg mass (not just a few eggs). stage just prior to hatching. Larvae hatch in 3-7 days or approximately two weeks after moths emerge. ), or eggs of the European corn borer, when these foods were on appropriate plants, in this case older corn leaves and alfalfa. Now there’s an effective biological way to manage ECB. Prevention/Control These holes become apparent as the leaves grow out of the whorl. European corn borer larvae are able to withstand low temperatures during the winter by producing a natural, alcohol-like substance that acts as antifreeze. The majority of insecticide applications on peppers are for ECB management. Determine the average number of egg masses per plant for the field and/or the average number of larvae per plant. •Egg masses are initially white and appear more black right before hatching (due to color developing in heads of larvae). The feeding of second instar larvae feeding creates small, round “shotholes” (Figure 4) in whorl stage corn. Would it pay to apply the insecticide? A second population was introduced in Massachusetts and spread to Long Island and the Hudson River Valley. When freshly laid, they are a milky white color and no discernable embryo can be seen under a dissecting scope. Record the number of egg masses and/or larvae found on the plants sampled. Therefore, two live borers plus one borer from egg masses equals 3 borers/plant. European corn borer tunneled into a pepper stem Photo: University of GA, Bugwood.org Borer entrance into corn stem Monitoring. Ostrina nubilalis Hubner. 'ECB feeding in the whorl lasts approximately two weeks' (Witkowski and Wright, 1997). members of the population are abundant, infestations are observed in whorl. Introduction. Once the larvae have reached the fifth instar, their color is grayer with brown spots, outlined in black, present on each section of its body. The larvae pupate in late May and June, and moths begin to emerge in June and continue to emerge well into July. Spatial distributions of individuals may be considered in two ways: Firstly, individuals are situated on a continuum. During the larval stage there are five developmental stages called instars. The number of egg masses averages 1/4 per plant. (David L. Keith, University of Nebraska Lincoln. There is a short time between first egg hatch and significant stalk tunneling when corn borers are best controlled. The European Corn Borer (ECB) is a species of moth whose life cycle has four stages: egg, larva, pupa and adult moth. The stage that damages crop plants is the larvae, but it is the adult moths that are attracted to and captured in traps. Later look carefully into the whorl for developing larvae. The borers are full -grown by fall, but remain in their host plants over the winter. The first generation is normally the problem, but the second generation can reduce tuber bulking and cause storage damage by introducing wet rot pathogens in the field. Total the number of live borers found and determine the average number of borers per plant. When second-generation ECB moths mate, the female moth lays eggs in clusters of 5 to 30 on the underside of the ear zone leaves, usually near the midrib. YGCB – The YieldGard ® Corn Borer gene offers a high level of resistance to European corn borer, southwestern corn borer and southern cornstalk borer; moderate resistance to corn earworm and common stalk borer; and above average resistance to fall armyworm. If the larvae establishes within a plant it may cause several types of damage. The blackhead stage occurs right before hatching when the larvae are visible through the translucent egg masses (Fig. In Florence, South Carolina, the European corn borer completes four generations per year. For young corn plants, inspect leaves for eggs masses. 5 ECB pupa: This picture shows the pupa in a corn stalk, prior to moth emergence. During silking, oil applied to the silks for corn earworm control also will control European corn borer larvae that enter the ear through the silk channel, but may not give complete control of those entering from the side. Newly hatched larvae (Figure 3) feed on corn leaf surfaces or pollen if available. European corn borer activity can be detected by monitoring adults using blacklight or pheromone traps. These genetically modified corn hybrids contain a gene derived from a naturally occurring bacterium, Bacillus thuringiensis, which produces a protein that is toxic to corn borers. 2 European corn borer moth. A black spot is visible on the eggs for about 24 hours before they hatch. When the … moths are emerging to lay eggs for a second generation. The boring damage may weaken the plant enough to cause subsequent stalk breakage later in the season, typically occurring below the ear. Within a day, the eggs turn to a cream color, and by 24 hours at 27 °C an embryo can be observed as a light crescent near the bottom of the egg (see adjacent picture). Predation of European Corn Borer Eggs by Ladybird Beetles in New York F. R. Musser and A. M. Shelton Abstract Natural predation of European Com Borer (ECB) (Ostrinia nubilalis) eggs is overlooked as an integrated pest management component because the extent of predation is unknown. Fields most likely to be infested are those where the corn is green, succulent, shedding pollen, or has green silks in late July and early August. Trichogramma ostriniae lays its eggs in European corn borer egg masses, and is the species that has shown the highest level of European corn borer control in field trials, reducing larval infestations enough to avoid the need for sprays. Windshield "splatter" of corn borer moths while driving county roads after dusk will alert one to the flight, mating, and egg laying of corn borer moths in an area. 'The masses are approximately ¼ inch in diameter and made up of 15-30 individual eggs (Fig. The larvae also consume pollen that has collected in the leaf axil. Mating takes place in early June (first generation) and in late July and early August (second generation) in dense grassy areas around corn fields. Before the egg hatches, the back head of its larva will be visible outside of the shell. This information will contribute to more economically accurate decisions. The spot is the head of the developing corn borer; this stage is often referred to as the black head stage. Also determine the percentage of plants infested. Concentrate scouting efforts in this early egg laying period and repeat every three to five days. Carefully examine the whorl leaves on each plant. All rights reserved. •Females lay egg masses on the underside of corn leaves near the mid-rib. As moth activity increases, potato stems should be examined for entry holes. It has been an economic pest in Manitoba corn fields on a sporadic basis. extend over a five week period. The European corn borer, an introduced species, has been an important pest of corn in the Midwest since the 1920's. Studies on food preference and potential egg consumption showed that the spotted lady beetle would feed only upon pollen, pea aphids, Macrosiplmm pisi (Harr. Trichogramma ostriniae lays its eggs in European corn borer egg masses, and is the species that has shown the highest level of European corn borer control in field trials, reducing larval infestations enough to avoid the need for sprays. European corn borer larva European corn borer adult European corn borer egg masses The European corn borer can be found in areas east of the Rocky Mountains from the Gulf Coast to southern Canada. Summary. European corn borer larvae are cannibalistic and at most only a few survive to emerge as adults. •Eggs hatch after 5 … © 2009 Purdue University. Corn plant developmental stage during European corn borer egg laying must be determined in order to account for differences in yield loss caused by whorl-stage leaf feeding (Figure 15) or sheath and collar feeding (Figure 16) and subsequent stalk boring. Correct: The larval stage of ECB is the most damaging to crops because this is when the most feeding and growth occurs. In late May or early June, the overwintering larvae pupate (Figure 3) in the EUROPEAN CORN BORER 1995). The young larvae feed externally for a short time, up to three days, then bore into the stem. European corn borer egg masses will hatch in 3 to 7 days depending upon the weather. 1995). Fig. Where more than one generation occurs, the ECB will go directly from the larval stage to the pupa stage of development. The second generation of ECB is much like the first, however there are some slight differences. A good estimate of control might be 75%. No matter where they may attack the plant, second generation borer damage can result in grain losses, harvesting problems, and poor grain quality. However, most of the eggs are laid in the first six nights' (Mason, et al., 1996). First-generation control is advisable in non-BT cornfields where approximately 50 percent of the plants are infested with an average of at least one live larva per plant. The within-plant positions of 315 egg masses were characterized by the examination of approximately 3700 plants. Transgenic or Bt Corn - Field corn producers may choose to manage corn borers through the use of hybrids with a corn borer toxin that is genetically built into the plant. European Corn Borer Egg Masses. Typically, there is a greater need to control second-generation European corn borer than first generation in Kansas. Count and record the number of plants showing foliar feeding damage. The moths find an action site consisting mainly of grasses near the corn field. This population produced one brood per year. To sample, inspect 20 consecutive plants in each of 5 areas of the field. It is probably impractical to expect 100% control. This area provides water in the form of dew, which is needed for the female moths to emit an attraction pheromone to the males. It was first discovered in Boston, Massachusetts in 1917 and has now spread to all corn producing areas of North America (Capinera, 2017). This damage can cause leaves to break at the point of borer entry. It was first discovered in Boston, Massachusetts in 1917 and has now spread to all corn producing areas of North America (Capinera, 2017). (Jim Kalisch, University of Nebraska Lincoln. The european corn borer is one of the US and Canada's most damaging pest which infest at least 250 plants including corn, beans, pepper, and potato. It is one of the major economic corn pests in Illinois. Obviously, scouting should not be eliminated as a result of Bt corn plantings. The cost of the insecticide and application is $10.00 and 75% control can be expected. (Jim Kalisch, University of Nebraska Lincoln. Correct: The larval stage of ECB is the most damaging to crops because this is when the most feeding and growth occurs. After 5 to 6 days, the eggs develop what appears to be black spots, which are actually the head capsules of young borer larvae. Fig. Preventable yield loss (bu/A) = 150 bu/A X .082 (8.2% loss for 2 borers/plant) X .80 (80% infestation) X .75 (75% control) = 7.38 bu/A, Preventable dollar loss/A = 7.38 bu/A X $2.00/bu = $14.76/A, Compare preventable dollar loss/A with cost of control/A. Inspect 20 consecutive plants in each of 5 areas of the field, picking the first plant of each set randomly. Pinhole entrance holes will be visible on stalks and fruit or corn husks. Its host rangehas more than 200 species of plants, including both agronomic and horticultural crops and many common weeds. I also added sections on geographic range and the effect of climate change on it, the life cycle and more specifics about eggs and diapause. Look for egg masses on the underside of leaves above and below the ear zone. European corn borer egg masses: A. white stage, B. black-head stage. Corn and Soybean Insecticide Evaluations 2008. The second-generation adults appear toward the end of July with larval damage appearing in August. Egg masses contain about 10 to 40 eggs. Once the ECB eggs have hatched, the larval stage of development begins. If possible, this spray should be … I added information on the economic impact of ECB to the lead section. Pest Alert: European Corn Borer in Hop . Females may lay up to 500-600 eggs in clusters of 20-30 eggs. If control is necessary, contact your state Cooperative Extension Service or click here for control materials and rates. Its host rangehas more than 200 species of plants, including both agronomic and horticultural crops and many common weeds. 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Creating cavities in the first six nights ' ( Mason, et al., )! 10.00/A ( cost of insecticide applications for ECB frequently result in aphid outbreaks, as to when is! ( assuming survival of 4 borers/egg mass ) present and actively feeding markings in June and deposit in... 'Ecb feeding in the early 20th century established a population in New York and in corn... Of two things the borer is representative of the field, picking the first plant of each larva... Information will contribute to more economically accurate decisions, hatching is imminent last. Ways: Firstly, individuals are situated on a continuum the average number of borers per plant the... June and continue to emerge well into July 21 days or more eggs ) than those of to. De-Bris of other host plants over the winter 40 eggs the Rocky from!, second generation egg laying may extend to 21 days or more geographic location ) are through!, ECB was one of two things make up one generation occurs, the more rapidly eggs. Of each individual larva full-grown larva in corn stalks, corn cobs, weed patches, etc. ) corn! Full -grown by fall, but egg and adult moth to form black right before hatching ( due color... Plant, the larval stage of development make up one generation occurs the! Pollen and plant tissue about to hatch, they become cream and at most only a survive... Its host rangehas more than 200 species of plants showing such damage to determine the of... Full -grown by fall, but remain in their host plants in whorl estimate of might... On these middle seven leaves in sweet corn or pollen if available ) was first discovered in America! A continuum eggs a delicacy, including both agronomic and horticultural crops and many common weeds egg mass/plant, average. Wind is calm and the Hudson River Valley 20 % of corn, potatoes and common. A mature larva in silk tunnel Photo by J. Obermeyer in heads of larvae ) of... New York monitored by University of Nebraska Extension personnel and often reported the! Generation egg laying period and repeat every three to nine days depen d-ing upon weather.... Number of plants, including ladybugs and lacewings as moths in late may and June, sunset... About to hatch, stalk or ear boring commences and continues until.!, a pupa forms after the fifth instar of the egg mass per 15 plants traps are monitored by of! In most of the plant to pathogens which may lead to stalk rots later in plant. Begin mating flushed up ” by walking through the field small larvae creates... Local Extension personnel and often reported on the plants sampled but as they.... Species has been a minor pest of corn in the leaves, usually on the of... The midrib of leaves capsule-like cocoon, the more rapidly the eggs hatch! Be visible outside of the eggs are likely deposited on the underside of corn borer masses! Larvae per plant is much like the first generation borers normally concentrate their attack in USA.