In Oklahoma, insect pests are a perennial problem that can cause reduced alfalfa productivity. These pests occur at various times of the growing season and reduce forage production in many ways.
Yellowing (chlorosis) and subsequent death of leaves (necrosis), along with stunting of plant growth, are caused by fluid feeding insects such as aphids and leafhoppers. The major aphid species include the pea, spotted, and blue alfalfa aphids. Another fluid feeder in alfalfa is the potato leafhopper.
During the spring and summer months, defoliation is a common form of damage in alfalfa. It is caused by the alfalfa weevil and several larvae. Extensive defoliation may cause significant forage yield reductions and can also reduce stand longevity if damage is severe and occurs repeatedly.
A third form of damage by insects is on new stands. During early spring and fall, larval stages of the army cutworm and fall armyworm may cause defoliation to the extent of removing all plant growth above the soil surface, and feeding by large populations may result in stand destruction. In addition, feeding by aphids during this same period can devastate young alfalfa stands, even when populations are low (<10 aphids/stem).
Still another type of damage caused by insect pests is destruction of new growth after cutting. This damage usually occurs after first cutting and is most often caused by variegated cutworms. Alfalfa weevil adults may also create a similar problem. This damage may lead to reduced growth and vigor while contributing to stand thinning. A thorough discussion of pest biology, damage, scouting, and economic threshold levels is provided in Oklahoma State University Circular E-826, “Alfalfa Production Guide for the Southern Great Plains.”
Pea and blue alfalfa aphids generally infest alfalfa fields beginning in March and may continue feeding through April and May. Spotted alfalfa aphids are usually associated with mild, dry weather conditions and may be active throughout the year. Historically, serious infestations have occurred in the fall, winter and early spring. Pea aphids are the largest of the species that occur in alfalfa. They are light green in color and possess a dark band at the base of each antennal segment. Blue alfalfa aphids are similar in appearance; however, they are usually smaller and bluish-green in color. In addition, the antennae have no bands, but gradually darken in color toward the tips. Spotted alfalfa aphids are small and yellowish-green with several rows of small, black dots along the dorsal surface. A magnifying glass or hand lens is essential in identifying these species.
The most damaging species are the blue and spotted alfalfa aphids. Both aphids cause obvious toxic effects (chlorosis and wilt) in plants while feeding. During the spring, plants can be severely stunted and are often killed when large numbers of aphids are present for several weeks.
The alfalfa weevil is the most damaging pest of alfalfa in Oklahoma. It overwinters as both eggs and adults. During mild winters in Oklahoma, larvae may appear late February or early March. However, activity generally begins in early spring with evidence of feeding on growing plant tips. Young larvae are yellowish in color, but as they mature, they turn green with black heads and possess a white stripe down the center of the back. For additional information on the development and management of the alfalfa weevil, refer to OSU Fact Sheet PSS-2091, “Alfalfa Weevil and Its Management in Oklahoma.”
In Oklahoma alfalfa, several species of foliage feeding caterpillars may be found throughout the summer. The species present include webworms, alfalfa caterpillar, green cloverworm, corn earworm, armyworm and yellow-striped armyworm. These defoliators are rarely a significant problem in established alfalfa, although seedling stands can be heavily damaged by their feeding.
Additional caterpillars that often occur at times of the year when alfalfa is particularly susceptible to defoliation include the fall armyworm, army cutworm and variegated cutworm. Fall armyworms may destroy newly planted alfalfa in the fall while army cutworms can destroy new stands in early spring. The variegated cutworm may do serious damage immediately following first harvest. Variegated cutworms that have hatched during growth of the first crop mature during first harvest and may destroy or delay regrowth of the second crop.
During mid and late summer, webworms may cause serious defoliation in Oklahoma alfalfa. They spin webbing over leaves and buds of alfalfa terminals and can cause losses in both seed and forage production. Insecticide applications for defoliators are most effective when larvae are small and/ or webbing (webworms only) is minimal.
For a detailed description of the larvae found in Oklahoma alfalfa, consult OSU Extension Fact Sheet EPP-7159, “Field Key to Larvae in Alfalfa.”
Blister beetles are slender, soft-bodied, black, gray or striped beetles from one-half to three-quarters of an inch long. Adults feed on foliage; however, larvae of species found in alfalfa are considered beneficial because they feed on grasshopper eggs. Blister beetles are gregarious, often congregating in large swarms within alfalfa fields. Swarms move frequently and are typically comprised of one or two species of small striped beetles. Blister beetles are important in alfalfa production, not so much for their foliage feeding, but because they produce cantharidin, a blister beetle defense, that is toxic to horses consuming hay that contains bodies of these insects that were killed in the harvesting process. Cantharidin is secreted from leg and body joints and is toxic even in dried bodies of dead beetles. Suggestions for management of blister beetles in alfalfa can be found in OSU Extension Fact Sheet PSS-2072, “Blister Beetles and Alfalfa.”
This small, wedge-shaped insect is light green and about one-eighth inch long. Feeding by this insect causes yellowing and necrosis of leaves that begins at leaf tips and is called hopperburn. Losses from this insect may occur during the summer months on new growth after alfalfa is harvested. Damage potential by this pest in Oklahoma is not well-known, but it is often found in numbers that are known to cause yield reductions in Midwestern states. In the Midwest, numbers as low as 0.5 leafhopper per sweep in 7-inch or shorter alfalfa are considered to exceed the economic threshold. Caution should be used in interpreting these thresholds for Oklahoma, since lower yields of summer cuttings in alfalfa may not justify money spent on control of potato leafhoppers.
During mid and late summer, several species of grass hoppers may migrate from field margins, fence rows or pastures into alfalfa. Border areas and seedling stands are particularly susceptible when field margin vegetation matures and dries. In addition, grasshoppers infesting alfalfa being grown for seed may feed on blossoms and seed pods, resulting in serious yield reductions.
As an alfalfa farmer dealing with mosquito larvae in the water of your alfalfa plants can be frustrating. Not only are mosquitoes a nuisance, but they can also spread diseases to humans and livestock. Eliminating mosquito larvae is key to disrupting their life cycle and preventing a larger infestation. In this article, we’ll explore effective methods for getting rid of mosquito larvae in alfalfa plant water.
Understanding Mosquito Breeding Habits
Before jumping into control methods, it’s important to understand how and why mosquitoes are breeding in your alfalfa plant water.
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Female mosquitoes lay eggs in stagnant water sources like plant trays, buckets, or puddles. The eggs hatch into larvae within days.
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Mosquito larvae feed on microorganisms and organic matter in the water They go through several growth stages over 5-14 days before transforming into flying adult mosquitoes
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Standing water from irrigating or watering alfalfa plants provides an ideal breeding ground if allowed to stagnate.
Prevention is the Best Strategy
Stopping mosquitoes from laying eggs in the first place is more effective than trying to eliminate larvae after the fact. Here are some key prevention tips:
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Change water frequently in alfalfa plant containers to prevent it from becoming stagnant.
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Eliminate standing water around plants by improving drainage.
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Use mosquito dunks or bits containing BTI bacteria in water containers. This biological control kills larvae but is safe for plants.
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Cover water containers tightly with lids or mosquito-proof netting.
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Introduce mosquito predators like fish or dragonfly larvae to water sources. They will feed on mosquito larvae.
Methods to Eliminate Mosquito Larvae
If larvae are already present, there are several effective DIY methods to get rid of them:
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Manually remove larvae by pouring water through a fine mesh sieve. This works for small infestations.
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Use a turkey baster to suck up and dispose of larvae floating at the water’s surface.
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Apply mosquito BTI in liquid or granular form. It’s a natural bacteria that kills larvae within 48 hours. Safe for plants when used as directed.
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Introduce mosquito fish like gambusia or guppies – they voraciously feed on mosquito larvae.
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Apply neem oil or essential oils like cinnamon or lemongrass to the water’s surface. Use extreme caution to avoid harming plants.
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Drain water sources completely and allow containers to dry out between waterings to break the mosquito life cycle.
Ongoing Prevention and Monitoring
Getting rid of current mosquito larvae is just one part of the battle. You also need to take steps to prevent future infestations:
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Dump and scrub water containers weekly to remove organic matter and eggs.
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Use fans or air pumps to agitate the water’s surface – mosquitoes won’t lay eggs on moving water.
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Check for and eliminate any small pools of standing water around your plants.
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Treat water with BTI bacteria monthly throughout mosquito season.
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Introduce predators like fish or dragonflies to permanent water sources.
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Monitor plants vigilantly and treat quickly at the first sign of larvae.
Controlling mosquito larvae takes diligence and persistence. But combining prevention, removal methods, and ongoing monitoring can help eliminate mosquito breeding in your alfalfa plant water. Properly managing water sources disrupts their life cycle and gives your plants a healthy head start.
Frequency of Entities:
Alfalfa: 16
Mosquito: 24
Larvae: 20
Water: 24
Plant: 16
Insecticide Usages on Alfalfa
The rules and regulations governing the chemicals used on alfalfa are quite rigid. This is especially true of alfalfa going into interstate commerce or alfalfa to be fed to lactating dairy animals or animals being finished for slaughter. The chemicals listed in this publication are all approved to be used at the concentration and with the limitations described. Any use of the chemical at different concentrations or a disregard for the limitations should be avoided.
Before using any chemical on alfalfa, check the toxicity, rates of application and limitations. The producer should also be aware that alfalfa is sometimes contaminated by chemical drift of pesticides being applied to adjacent fields. Remember that all pesticides should be handled with care.
Stop Mosquito Bites or Hatching Larva at Home
FAQ
What can I put in my plant water to kill mosquito larvae?
How do you stop mosquito larvae in water?
Will vinegar in water kill mosquito larvae?
What essential oil kills mosquito larvae in water?
How do you get rid of mosquito larvae?
If you find mosquito larvae or a raft of eggs on your property, there are a few different ways that you can get rid of them. If they are living in a water source that you can tip over or pour out, simply do so. Many times, however, there is no way to eliminate the budding mosquitoes without introducing something to the water.
How to kill mosquito larvae in standing water?
If you want to kill mosquito larvae in standing water with regular household products, you can use apple cider vinegar, dish soap or shampoo. You can even use oils such as vegetable oil, extra-virgin olive oil or essential oils, like cinnamon oil. Although you can use bleach, you have to be careful because bleach can harm pets and wildlife.
Does vinegar kill mosquito larvae?
Yes, white vinegar (and apple cider vinegar) will kill mosquito larvae. To be effective, you must use a ratio of 15% vinegar to 85% water. What can I put in my water tank to kill mosquito larvae? At this time, we are not aware of anything you can put in a drinking water tank to kill larvae that will leave your water safe to drink.
Does soap kill mosquito larvae?
Any liquid soap can kill mosquito larvae, so all you have to do is grab some dish soap or shampoo and add it to the standing water. A millimeter per gallon of standing water will kill the mosquito larvae in about a day. Oil is a super quick solution when it comes to killing mosquito larvae.