The Impact of Beauveria bassiana, Trichogramma, Bt Sprays, and Spinosad on the Lepiodpteran (Crambidae) Cereal Stalk Borer- The European Corn Borer (Ostrinia nubilalis)

Final Report for GNC07-084

Project Type: Graduate Student
Funds awarded in 2007: $10,000.00
Projected End Date: 12/31/2009
Grant Recipient: Bowling Green State University
Region: North Central
State: Ohio
Graduate Student:
Faculty Advisor:
Daniel Pavuk
Bowling Green State University
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Project Information

Summary:

The results of this study indicated intensive infestation of stalks, lots of European corn borer larvae in the stalks, lots of tunnels, much infestation of cobs and a yield loss of corn in the control treatments. There was also a considerable infestation of the stalks by the European corn borer larvae, a good amount of larvae and a number of tunnels, and infested cobs which consequently affected the yield in the treatment with Trichogramma pretiosum. The explanation for this is that in the control treatments there was simply the lack of control of the European corn borer in those plots. Whenever there is infestation of pests and control measures are not implemented, the results will be destruction of the crops resulting in decreased yield of the same. In the treatment 2 (with Trichogramma pretiosum), it could be that:
a) it is always difficult to contain the Trichogramma pretiosum in the same plots. They are flying insects and are prone to wander around or fly away to distant places;
b) There is a major limitation to the use of Trichogramma pretiosum due to reduced efficacy under conditions of heavy rainfall, sunshine and high temperatures (J. Chihrane and G. Lauge, 1996). There was a week when the temperatures were over 90 0F during this research;
c) In addition to reducing the efficacy of parasitism by Trichogramma pretiosum, high temperatures cause male sterility and reductions in the rate of wasp emergence from the capsules.

The other treatments 3, 4, 5, 6, and 7 provided a considerable amount of control of the European corn borer in almost all parameters for both years and especially in the year 2007.

Throughout this research Spinosad has emerged as the most effective biological agent in the control of the European corn borer. Treatments 3 in all parameters have shown the efficacy of Spinosad in controlling the European corn borer larvae. The general trend so far has been that these biological agents have increased the mortality of the European corn borer larvae. The infections on corn have been very severe in all the control treatments while the different treatments have imposed various degrees of restraints on the European corn borer population. In all the parameters there has been a significant difference between the control and other treatments with a P value of <0.001. While the tradition control methods of using insecticides are sometimes environmentally hazardous, and fail to control the European corn borer larvae when the larvae are in the tunnels, these novel (underutilized) biological control methods if extensively used would provide good control measures in an integrated pest management. They would provide farmers an economically effective and environmentally sound approach to the management of the European corn borers. This is so because one of the Biological agents, Beauveria bassiana by the help of its conidia would grow into the tunnel of the stalk develop into hyphae which proliferate and kill the larvae inside the stalk. Beauveria bassiana also has no preference as to its host’s stage in life; it will attack larvae and adults. A very unique characteristic is that it affects its host upon contact, unlike many other pathogens that need to be consumed to cause infection. Upon contact the pathogen kills the host from the inside out. It produces spores, known as conidia (asexual form), that directly infect through the outside of the insect’s skin; it then proceeds to germinate. From the spores it secretes enzymes that attack and dissolve the cuticle. It also produces Beauvericin, a toxin that weakens the host’s immune system. This research finding is relevant in boosting underutilized control strategies and increasing stakeholder adoption of integrated pest management practices and thereby reducing the use of conventional insecticide. The results are good and relevant for increasing farmers’ adoption of Integrated Pest Management practices, reducing the use of conventional, broad-spectrum chemicals for Ostrinia nubilalis control and employing less environmentally harmful insecticides. By adopting less broadly toxic chemicals in pest management, control by natural enemies of European corn borer, such as Parasitoids such as Trichogramma pretiosum and microbial pathogens may be enhanced and this would in turn reduce the need for chemical controls and make row crop farming more profitable for the farmers. The results of the research done on the abundance and composition of the non-target arthropods in the treatment plots clearly show that the different treatments applied to various plots had no effect on the distribution and abundance of these non-target arthropods. All the P values obtained by one way ANOVA were bigger than 0.05.

Introduction:

Maize (Zea mays) or corn, together with wheat and rice are the major cereal crops grown around the world (at least by 53 countries) (FAO Stat.2001). It ranks third in production following wheat and rice. Maize is the world’s most widely grown crop in almost all tropical areas of the world, including the tropical highlands over 3000 m in altitude as far North as the 65th latitude to temperate areas. Because of different ecological conditions that exist between the temperate areas and the tropics, the insect vectors and their disease agents also are different under these different conditions (Tsai and Falk 1999). Maize is an extremely important crop grown in the United States, Europe and Africa for both human and livestock consumption. Of the various pests that attack maize/corn in Africa, the Lepidopteran stem /stalk borers are by far the most injurious, particularly the Chilo partellus (Rami Kfir. 2002, Youdeowi 1989). In the United States (Ohio, Minnesota, Iowa and other Corn Belt states), there are a number of pests that attack corn and the European corn borer-Ostrinia nubilalis (Lepidoptera: Crambidae) is one of the most destructive pests. It significantly affects growth and production of corn.

The European corn borer came to North America during the early 1900s, possibly in broom corn imported from central Europe (Hungary and Italy). It was found in the North Central States in 1921. It spread slowly from Southern Michigan and Northern Ohio. The European corn borer, Ostrinia nubilalis is the most damaging insect pest of corn throughout the United States and Canada. Losses resulting from the European corn borer damage and control costs exceed $1 billion each year (Mason et al. 1996, University of Minnesota 2002). During a 1995 outbreak, losses in Minnesota alone exceeded $285 million. A recent four-year study in Iowa indicated average losses of nearly 13 bushels per acre (826.3 kg/ha) in both first and second generations of European corn borer, for total losses of about 25 bushels per acre (1589 kg/ha).

Damage to corn from the European corn borer has increased in Europe in the last several decades. This increase may be due to environmental changes, the significant increase in monoculture corn acreage, the introduction of more susceptible hybrids, and the increased use of pesticides, which could be reducing predator/parasites populations. (Cordero. et al. 1998).

To avoid total loss of corn, insecticides are often used by farmers to control the European corn borer. The use of insecticides such as Lorsban 4E (Chloropyrifos), Intrepid 2F (Methoxyfenozide), permethrin (liquid Ambush or granular Pounce), lambda (cyhalothrin) and furadan (carbofuran) has been very common, especially before the larvae tunnel into the corn stalks. However, scouting for European corn borers, especially second generation borers is hard exercise and timing an insecticide application for maximum efficacy is difficult. Many producers did very little to manage European corn borers in Illinois and some Midwest States (Rice and Ostlie, 1997). But overuse of insecticides is not economically sound and is environmentally hazardous. For example diazinon has a very high toxicity on fish, bees and birds, while permethrin has a very high toxicity to fish, and on bees, and low toxicity to birds. In recent years, elevated awareness of the impacts of pesticide use on the environment and human health has resulted in efforts to reduce reliance on chemical control. Many countries have instituted more stringent regulations on pesticide manufacture, registration and use, thereby increasing the cost and decreasing the availability of these tools. The need for alternatives to pesticide use is very clear. A recent report by the U.S Congress, Office of Technology Assessment (U.S congress, OTA 1995) indicated that biologically based technologies such as biological control could be more widely used to solve pressing needs in pest management.

Project Objectives:

The research had the following objectives:

1.To compare the efficacy of Bacillus Thuringiensis (Bt) spray, Dipel Beauveria bassiana, Trichogramma pretiosum and Spinosad for the economic control of Ostrinia nubilalis.

2.To assess the impact of these treatments on the abundance and composition of non-target arthropods.

Cooperators

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  • Rostern Tembo

Research

Materials and methods:

The research involved setting up a complete random design at the Northwestern Branch of the Ohio Agriculture Research and Development Center (OARDC), one of the field research facilities owned by Ohio State University and located in Wood County, Ohio. The randomized complete design for this research consisted 35 plots and 7 treatments. Each plot was 12.2 Meters in length by 12.2 meters in width. Each plot had been separated from the next plot by 12.2 meters in length by 6.1 meters buffer that was cultivated every week to remove weedy vegetation and reduce the movement of arthropods between plots. Beck 5222 variety non Bt Corn was planted on 16 rows using reduced tillage practices and standard fertilization procedures. Each plot had 16 rows of corn. A rough estimate on plants per row was 65-70 stalks. Each plot had approximately 900 stalks. Pheromone traps were set to help us determine the exact time when the moths would be flying and when to start the treatments.

Seven different treatments that were used during the whole research

Treatments: Entomopathogen/CROP

1: Control/Corn
2: Trichogramma pretiosum/Corn
3: Spinosad/Corn
4: Beauveria bassiana/Corn
5: Bt Sprays/ Corn
6: Beauveria Bassiana/& Bt spray/Corn
7: Trichogramma & Spinosad/Corn

Corn was planted during the second week of May (8th May Monday 2006 and May 10 2007 at 2:00 pm) as was a common agricultural practice by producers in the Northwestern Ohio area. Preemergence herbicide (Lexar 3.25 qt/acre, Round up 22 oz per acre and 2.4 D Ester 1 pt per acre) was applied, and postemergence herbicide (accent 2/3 oz per acre, crop oil concentrate 1% v/v, 28% 3 qt, and Basagran 32 oz per acre) were used as necessary to control weed populations within plantings.

Fifteen to twenty egg masses of Ostrinia nubilalis were pinned to the undersides of corn leaves in each of the plots to correspond to the approximate flight period of the first generation, which is usually mid to late May through early June. These egg masses were attached to the center 5 rows of each plot, 2 meters from each end of the set of corn rows, to avoid possible edge effects. After attaching the egg mass to the leaf of one stalk, there were ten stalks in between which were omitted before another attachment of the egg mass was done on another leaf of another stalk in the same row. The same procedure was maintained for all the rows and in all plots. Egg masses were examined every day until hatching; any eggs showing evidence of disease were removed and immediately replaced. The egg masses were also checked daily for any evidence of predation by ladybird beetles or other predators such as Orius insidiosus. The same procedure was used to place the egg masses in the blocks to correspond to the flight of the second generation moths in late July or early August. Plot number 1 was a control plot, with no treatment applied. Plot 2 had the Trichogramma pretiosum parasitized eggs which were attached to the leaves of corn by way of stapling the strips containing the parasitized eggs to the leaves of corn on the same day the attachment of the egg masses of European corn borer was done. The Trichogramma pretiosum takes one or two days to hatch out. Trichogramma pretiosum parasitizes the eggs of the European corn borer and so when the European corn borer hatched out, within one week, the Trichogramma pretiosum was not required. In this case they hatched out before the eggs of the European corn borer did, and were able to parasitize the European corn borer eggs. That was desirable because the parasitoids tend to move out of the plot where they emerged.

The spraying methodology was as follows:
In 2006, all the sprayings were done by using the portable back pack sprayer. Spinosad: 20 mL of Spinosad per 3.78 liters of water (1 gallon of water). The sprayer used was a 3 gallons (11.34 Liters) sprayer. So for 11.34 Liters (3 gallons) of water, 60 mL of Spinosad was used. This was enough to spray two plots of Spinosad treatment. Another similar mixture and a half was made for the remaining three plots of Spinosad.
Beauveria bassiana: 25 mL of Beauveria bassiana per 3.78 liters (1 gallon) of water. The sprayer was a 11.34 liters, so 75 mL of Beauveria bassiana was used to make a solution. This was enough for two plots only, and another mixture and a half was made for the other three plots.
Bt spray: 38g of Bt granules per 3.78 liters of water (1 gallon). For 11.34 Liters (3 gallons sprayer), 114g of Bt granules were dissolved in a sprayer of water. This was enough for two plots of Bt treatment, and again another similar mixture and a half was made for the other plots.

In 2007 a tractor was used for all sprayings for both 1st and 2nd generations of the European corn borer. Spinosad: 20 mL of Spinosad per 3.78 L (1gallon) of water. Beauveria bassiana: 25 mL of Beauveria bassiana per 3.78 L of water. Bt spray: 38g of Bt granules per 3.78 L of water.

Since spraying was done by the tractor, changes had to be made on the volume of water used (conforming to the tank size of the tractor) and the volume of the microbial agents as well. We used 60.48 L (16 gallons) of water per each trip of spraying. Therefore, 320 mL of Spinosad was mixed with 60.48 L of water, 400 mL of Beauveria bassiana was mixed with 60.48 L (16 gallons) of water and 602.3 g of Bt spray was mixed with 60.48 L of water. Each plot was 12.2 meters x 12.2 meters = 148.8m2. There were 5 replications of each of the 7 different treatments. Five plots multiplied by 148.8 m² per plot = 744 m² per treatment. 744 m2 / 4046.8 m2 per acre = 0.1838 acres per treatment. We used water as a carrier at a rate of 75.6 L/acre. 75.6 L/acre x 0.183 acres per treatment = 13.8 L of water (carrier) needed per treatment. We rounded this up to 15.12 L. We needed at least 15.12 L to keep the machine pumping at a constant rate therefore to allow for priming the system and making sure the previous product was purged from the lines we mixed 30.24 L of solution for each treatment. This may seem excessive but it was necessary to have this much guarantee, we had an adequate amount of solution to complete all the plots. We mixed microbial agent with 60.48 L of water so that we could complete 2 treatments with each load.

Plot 3 was sprayed with Spinosad as soon as the European corn borer larvae became visible. This was both during the first and the Second generation of the European corn borer. Spinosad so far does not pose any risks to mammals, birds, fish and beneficial insects like the pollinators, but highly active on larvae of certain insects including species from the orders of Lepidoptera, Diptera, Hymenoptera, Thysanoptera and a few Coleoptera (Dow AgroScience LLC 2001).

Plot number 4 was sprayed with the Beauveria bassiana. Plot 5 had been sprayed with Bacillus thuringiensis sprays. Plot 6 had a combination of Beauveria bassiana and Bt Spray, and plot 7 consisted of both Trichogramma pretiosum and Spinosad treatments.

Data Acquisition

Parameters were established to determine the level and extent of damage to the stalks and corn by the European corn borer larvae. These parameters were: number of infected stalks per plot, the number of larvae found per stalk per plot, number of tunnels per stalk per plot, Length of tunnels per stalk per plot, number of infected cobs per stalk per plot and the yield per plot.

During mid August, 20 stalks of maize/corn were randomly (to void being bias) selected from each plot and were visually sampled for damaged stalks, Ostrinia nubilalis larvae per stalk, number of tunnels per plant, tunnel length per plant, and infected cobs recorded. The mean was then calculated for each parameter. Random sampling ensures that each member of the population has an equal and independent chance of being chosen as a member of the sample, but the selection of any member of the population must in no way influence the selection of any other member. During harvesting time, the total yield per plot was also noted in bushel (equal 8 gallons, it’s an old volume measure of cereals) per acre. The calculated data were statistically analyzed by first doing Normality Test(to see the normal distribution of the data) and then later statistical analysis using Minitab 14, one-way ANOVA and differences between parameters were obtained by using Tukey post-hoc comparison test.

Sampling of Non-Target Arhtropods

The random sampling process of insects started three weeks after the application of treatments. Movement through each plot was a random walk and the beat – stick method of sampling was used. The beat stick method equipment consisted of a cut broomstick approximately ½ m. in length and a home tray (where arthropods fell after gently beating the stalk of corn with a stick), a jar (1000cm3 in volume) with less than 100cm3 of ethyl acetate solution in it, and a net for trapping the arthropods. There were also a number of plastic bags. After opening and closing of the jar, the smell of the ethyl acetate could diminish and insects could take long before they died. During that time some of the arthropods could were put in plastic bags until I came back to the lab where I could refill the jar with new Ethyl acetate. This method of collection concentrated on free moving or flying arthropods. Any insect arthropod that was seen on the corn leaves, stalk or tassels was trapped by a net and after catching it was put in a jar containing ethyl acetate solution (which kills arthropods within few minutes). Some arthropods could fly away after falling on the tray and it was at that time that the net proved very essential because they could be trapped by the net and caught.

During both years 2006 and 2007 identification of the arthropods was done in the lab when the whole process of sampling was over. Sampling arthropods was always done on days that were clear and dry and with a minimum temperature of at least 70 degrees Fahrenheit.

Research results and discussion:

There was more infestation by the European corn borers in the stalks of corn in the control treatment than in the other treatment plots. The control treatments had a mean of 17.0 infected stalks per plot, while the other treatments had much lower infestation levels. There was a significant difference between the control treatment and the other treatments. One way ANOVA: (DF = 6, 28, F =14.73, P < 0.001). There was very little infestation of stalks of corn from Spinosad treatment and Trichogramma pretiosum plus Spinosad with a mean of 3.4 (±0.98 SE) and 4.8 (±1.2 SE) respectively of the sampled stalks. The 2007 results were somewhat similar to the results obtained in 2006. There was no noticeable difference between the Control treatment and treatment with Trichogramma pretiosum. But there was a significant difference between the Control treatment and other treatments (One way ANOVA – DF = 6, 28, F = 9.83 and P < 0.001). There was more infestation of the stalks in control treatment and treatment with Trichogramma pretiosum with an infestation mean of 20.0 (± 0.0 SE) and 19.6 (± 0.4 SE) respectively. The trend seems to be very similar with that of 2006. The greatest number of larvae per stalk was found in the control treatment followed by the treatment with Trichogramma pretiosum. The control treatment had a mean of 34.8, while the other treatments had less than that. There was a significant difference between treatment with Spinosad and treatment with Trichogramma pretiosum plus Spinosad with the other treatments. One way ANOVA – DF =6, 28, F = 14.37 and P < 0.001. There were fewer larvae per stalk in Spinosad treatment with a mean of 9.8 (± 0.58 SE) and Trichogramma pretiosum plus Spinosad with a mean of 8.6 (± 1.86 SE) than in any other treatments. The 2007 results were almost similar to the 2006 results. The highest number of larvae was found in the control treatments with a mean of 29.4 followed by the treatment with Trichogramma pretiosum mean of 25.8. There was a significant difference between treatments with Spinosad and the other treatments. One way ANOVA – DF =6, 28, F = 7.03 and P < 0.001. There were fewer larvae per stalk in Spinosad treatment with a mean of 6.0 (± 1.48 SE) followed by treatment with Trichogramma pretiosum plus Spinosad with mean of 10.8 (± 1.16 SE) than in the Control treatment which had a mean of 25.8 (± 3.38 SE). There were more tunnels in the stalks of corn from both control treatment and treatments with Trichogramma pretiosum with a mean of 24.2 (± 3.8 SE) and 25.4 (± 2.44 SE) respectively. There was a significant difference between the Control treatment and treatments with Spinosad and Trichogramma pretiosum plus Spinosad. One way ANOVA – DF = 6, 28, F = 9.09, and P = < 0.001. Treatments with Spinosad and Trichogramma pretiosum and Spinosad had low numbers of tunnels (mean of 6.6 (± 0.4 SE) and 7.6 (± 7.6 SE) respectively) per plant compared to the rest of the treatments. In 2007, there were more tunnels in the control treatment with a mean of 44.8 cm (± 3.06 SE) followed by the treatment with Trichogramma pretiosum with a mean of 36.6 cm (± 3.82 SE) than any other treatments. There were few tunnels in Treatment with Spinosad with a mean of 11.8 cm (±1.28 SE). There was a significant difference between Control treatment and treatment with Spinosad. One way ANOVA – DF = 6, 28, F = 14.18, and P < 0.001. There was no significant difference between Control treatment and the treatment with Trichogramma pretiosum. Both treatments had long tunnels means of 32.6 cm (± 2.3 SE) and 32 cm (± 5.4 SE) respectively. However, Control treatments and treatment with Trichogramma pretiosum differed significantly with treatments with Spinosad, Beauveria bassiana and Bt spray and Trichogramma pretiosum plus Spinosad. One way ANOVA – DF = 6, 28, F = 6.96 and P = < 0.001. The shortest length of tunnels was recorded in treatment with Spinosad Trichogramma pretiosum, with a mean of 6.8 (± 1.7 SE) and also in treatment with Spinosad with a mean of 14 (± 3.3 SE). In 2007, the longest tunnels were also in Control treatments and in treatment with Trichogramma pretiosum with a mean of 46 (± 1.9 SE) and 39 (± 3.86 SE) respectively. The shortest lengths of tunnels were in Treatment with Spinosad with a mean of 12.4 (± 1.5 SE). There was a significant difference between the length of tunnels in Control treatment and the lengths of tunnels in other treatments (One way ANOVA - DF = 6, 28, F = 15.88 and a P<0.001). The highest infestation of the cobs was recorded in Control treatment with a mean of 17.4 (±2.0 SE) and treatment with Trichogramma pretiosum which had a mean of 13.4 (± 1.3 SE). There was no significant difference between Control treatment and treatment with Trichogramma pretiosum. The lowest infestation of the cobs was in treatment with Spinosad. There was a significant difference between Control treatment and other treatments. One way ANOVA – DF = 6, 28, F = 7.08 and P < 0.001. There was also low infestation of cobs in treatments with Bt sprays and treatment with Trichogramma pretiosum plus Spinosad. In 2007, the highest infestation of cobs was in Control treatment with a mean value of 14.2 (± 0.73 SE) followed by treatment with Trichogramma pretiosum with a mean of 11 (± 1.14 SE). There was no significant difference between Control treatment and treatment with Trichogramma pretiosum. There was a significant difference though between the Control treatment and other treatments. One way ANOVA – DF = 6, 28, F = 20.19, with a P < 0.001. The lowest infestation of cobs was recorded in treatment with Spinosad. The yield was quite lower in the Control treatment with a mean of 7847.11 (±1196 SE) kilogram per hectare, than the rest of the treatments, followed by that of treatment with Trichogramma pretiosum with a mean yield of 9942.04 (± 484.88 SE) Kilograms per hectare. One way ANOVA – DF = 6, 28, F = 2.49 and P < 0.046. The highest yield was in treatment with Trichogramma pretiosum plus Spinosad with a mean yield of 10797.56 (± 664.03 SE) kilograms per hectare followed by that of Spinosad with a mean yield of 10756.89 (± 376.22 SE) kilograms per hectare (Figure 8). There was a significant difference in the yield between the Control treatment and treatments with Spinosad, Beauveria bassiana and Trichogramma pretiosum plus Spinosad (One way ANOVA; DF = 6, 28, F =2.49 and P<0.046. In 2007, the yield was slightly lower in treatment 1 than in the other treatments. In the control treatment the yield mean was 10360.28 (±293.8 SE) kilograms per hectare while in the other treatments the yield was higher than that. The highest yield was in treatment with Spinosad, with 11515.8 (± 110.2 SE) kilograms per hectare followed by treatment with Trichogramma pretiosum plus Spinosad with a mean yield of 11335.28 (± 153.2 SE) kilograms per hectare. There was no significant difference between the yield in the Control treatment and the yield in other treatments. One way ANOVA; DF = 6, 28, F = 1.49, and P= 0.217. Yield losses due to the European corn borers can vary from year to year according to the levels of infestation, and I think are generally unpredictable from one year to the next. Yield losses are primarily physiological losses from reduced plant growth. Stalk tunneling results in shorter plants with fewer and smaller leaves. Movement of water and nutrients can be restricted over the entire kernel- filling period. During the period of kernel growth, there is between 5 and 6% loss in grain yield for each larva per plant. During corn development stage, the loss per plant is about 2 to 4% (Mason C. E. et. Al. 1996). Most yield losses can be attributed to the impaired ability of the corn plants to produce normal amounts of grain due to physiological effect of larvae feeding on the leaf and conductive tissues. Results of Insect Sampling During 2006 and 2007 sampling of insects was done in all the 35 plots. Most arthropods sampled from different plots with various treatments were in the order of Coleoptera (Coccinella septempunctata, Popillia japonica and Diabrotica virgifera virgifera), Hemiptera (Euschistus variolarius), Hymenoptera (Andrena imitatrix Cresson), and Orthoptera (Neoconocephalus and Melanoplus femurrubrum). The reason may be for having sampled few orders of arthropod could be that the changes in corn plants growth levels could have potentially affected the arthropod orientation and interaction with the plants, and not the microbial agents. For arthropods that feed on pollen (at that stage pollen had fallen off) the changed plants could for example offer less pollen as food source. A decrease in arthropod species availability would eventually affect other arthropod populations that fed on those arthropods from the decreased population. Andrena imitatrix Cressons need both suitable nesting sites and pollen plants (Gathmann et al. 1994). Parasitoids depend on spatially and temporally co-occurrence of hosts and nectar (Russell 1989). Some monophagous insect herbivores may spend their whole life on one host plant, feeding, copulating and ovipositing (Zwolfer and Harris 1971; Tscharntke 1999), and these could be the ones that were sampled. In both years the collection was dominated by the Diabrotica virgifera virgifera in all the plots while the least were the bees and the moths. The following were the average insects that were sampled in all the plots. Analysis of variance (ANOVA) was used to determine if any significant difference occurred between treatments. The data were statistically analyzed by using Minitab 14, one-way ANOVA and differences between parameters could have been obtained by using Tukey post-hoc comparison test, but there were no significant differences between the control treatment and the other treatments. The analysis showed no significant differences between the insects sampled from the control treatments and the other treatments. The P values obtained by one way ANOVA were greater than 0.05. The number of Diabrotica virgifera virgifera was quite high in all the plots, Minitab 14: One way ANOVA – DF =10, 24. F = 0.77. P = 0.657. So far the statistical analysis done regarding the abundance and composition of the non target arthropods in all the plots for both years, showed no significant difference. The results clearly show that the different treatments applied to various plots had no effect on the distribution and abundance of these non-target arthropods.

Participation Summary

Project Outcomes

Project outcomes:

This research finding is relevant in boosting underutilized control strategies and increasing stakeholder adoption of integrated pest management practices and thereby reducing the use of conventional insecticide. The results are good and relevant for increasing farmers’ adoption of Integrated Pest Management practices, reducing the use of conventional, broad-spectrum chemicals for Ostrinia nubilalis control and employing less environmentally harmful insecticides. By adopting less broadly toxic chemicals in pest management, control by natural enemies of European corn borer, such as Parasitoids such as Trichogramma pretiosum and microbial pathogens may be enhanced and this would in turn reduce the need for chemical controls and make row crop farming more profitable for the farmers.

Farmer Adoption

The results of this research investigation suggest that microbial controls and the use of Spinosad in the control of European corn borer in non-transenic field corn has genuine potential for adoption by growers in the United States and in other countries.

Recommendations:

Areas needing additional study

The results of this research project indicate that much more study is needed in the area of biological control of the European corn borer. The use of microbial insecticides and natural enemies, such as Trichogramma, has much potential in improving effective management of European corn borer populations in field corn.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.