When To Spray For Soybean Aphids?

The recommendation is to avoid spraying soybean aphids due to their late arrival and limited infestation within a field. Evaluations are conducted at two locations every summer, with a two-year summary from the ISU Northwest Research Farm, near Sutherland, IA. Soybean aphids were counted on whole plants from June through September. Fields that received early prophylactic insecticide sprays may have few natural enemies to keep colonizing aphids at bay.

The recommended threshold for soybean aphids is 250 aphids per plant, with 80 or more of the plants infested and with aphids. Many years of research have consistently shown that there is no yield benefit to spraying for soybean aphids after seed set is complete (R6 growth stage and beyond). If soybean rust is present and being sprayed when soybean aphid thresholds are met, a fungicide/insecticide tank mix should be effective.

Some scouts and farmers haven’t seen soybean aphids until very recently, where plants are reaching full seed set (R6). Spraying pesticides when an infestation occurs early in the season doesn’t pay off. Spraying flowering soybean poses a threat to honey bees, so communication plans should be communicated to nearby beekeepers and follow label precautions to minimize honey bee kills.

The recommended time to begin scouting is when soybeans are in the late vegetative stage (late June/early July in Midwest states). Growers should continue their watch through pre-flower and flowering stages and treat if aphids reach the economic threshold. The critical time to scout for aphid populations is during the R1 through R5, which is currently in Nebraska, and a majority of the Corn Belt is soybean aphids usually reach the economic threshold and require treatment in late July through August.

When To Treat Soybean Aphids In Nebraska?

Los pulgones de la soja en Nebraska generalmente alcanzan el umbral económico y requieren tratamiento entre finales de julio y agosto. Este tratamiento es suficiente para evitar que las poblaciones de pulgones resurjan antes de abandonar los campos a finales de agosto y principios de septiembre. La gestión de los pulgones de la soja incluye su identificación, ciclo de vida, daños y métodos de control. Se recomienda realizar muestreos y aplicar insecticidas foliares a tiempo para proteger los rendimientos y retrasar la resistencia genética a los insecticidas.

La resistencia de las plantas huésped es una nueva herramienta de regulación. Aunque se puede encontrar un número reducido de pulgones a finales de junio, los agricultores deben comenzar a inspeccionar los cultivos regularmente, ya que la población de pulgones puede aumentar rápidamente, y estar preparados para tratar si es necesario. Las pulverizaciones pueden ser más efectivas si no se combinan insecticidas con herbicidas, debido a que sus métodos de aplicación son diferentes.

Sin embargo, la mezcla con fungicidas ha mostrado ser efectiva. Durante la etapa de crecimiento R5, se justifica el tratamiento si se encuentran un promedio de 250 pulgones por planta en más del 80% de las plantas del campo. Además, la gestión integrada de plagas (IPM) para los pulgones de la soja contempla tácticas culturales, genéticas, económicas y químicas. Es crucial empezar a monitorear los campos de soja al menos una vez por semana a finales de junio y principios de julio, para asegurarse de que la población de pulgones no alcance niveles críticos que puedan afectar el cultivo.

What Stage Do You Spray Soybeans?

Indeterminate soybeans initiate flowering at the R1 growth stage, around the summer solstice (June 21). This stage is significant as it aligns with the recommended application period for many herbicides. When scouting soybeans for fungicide application, identifying the growth stage across the field is crucial, with R3 being the ideal stage for applying fungicides. Research indicates that a robust soybean stand, specifically over 100, 000 plants per acre sown from late April to mid-May, can endure wheel tracks from R1 spraying. Additionally, a second fungicide application can be performed up to the bloom stage, with at least five days between sequential treatments.

For herbicides like Roundup PowerMAX, seasonal use is limited to 64 oz, with optimal spraying times for herbicides being between 9 a. m. and 6 p. m. to enhance weed control. In dealing with white mold, it’s beneficial to use fungicides in two applications spaced two weeks apart, and utilizing Cobra separately can help mitigate mold issues. Fungicides offer two to three weeks of disease suppression; however, they are not systemic.

To maximize yields, the optimal fungicide application timing is between R2 (full flower) and R3 (first pod). Early spraying can effectively manage fungal growth, especially in the canopy. The Hefty Brothers emphasize the importance of timely herbicide treatment before flowering, with specific limitations on herbicide applications after certain growth stages. Proper monitoring of seed color indicates readiness for safe spraying.

Is Spraying Aphids A Good Idea In Iowa?

Research has demonstrated that there is no yield advantage in spraying for soybean aphids after the R6 growth stage. Since 2001, foliar insecticides, particularly pyrethroids and organophosphates, have been the primary approach to managing soybean aphid populations in Iowa. Despite generally low populations in recent years, a surge occurred this summer with high numbers and visible symptoms like honeydew and sooty mold. Over the past years, evaluations were conducted across various locations, including the ISU Northwest Research Farm, where numerous treatments were tested.

Regular scouting is essential to determine when to treat, as spraying is ineffective once seed set is complete. The continued prevalence of soybean aphids (Aphis glycines) makes them the most significant pest for soybean farmers in Iowa. Notably, since 2010, these pests have begun colonizing corn later in the summer. Farmers are advised against using insecticides if aphid pressures are not present. If thresholds are exceeded, targeted treatments with products like Pyrethrum or strong water sprays can be considered.

For eco-friendly control, soapy water or a strong spray of water can dislodge aphids from plants. Overall, it is crucial to monitor aphid populations continually to ensure effective pest management and protect yield potential.

When Should You Not Spray Insecticide?

Insecticides pose the highest risk to animals while wet, necessitating that pets be kept away from treated areas until the chemicals dry completely. It is advisable to avoid insecticide application during rain or before anticipated rainfall, as this can result in improper drying and may allow chemicals to leach into soil and water, impacting wildlife. Optimal insecticide application occurs on calm, overcast days, particularly in early spring when pest populations are minimal, allowing for effective pest control and minimizing the insecticide's workload.

Certain situations warrant avoiding insecticide use entirely, particularly when beneficial non-target species may be present, such as bees and pets. It is essential to apply pesticides at appropriate times—early morning or late evening—when environmental conditions—such as lower temperatures and reduced wind—help mitigate evaporation and chemical drift, and protect beneficial insects.

For safety, individuals should remain out of treated areas for a minimum of 12 hours, unless otherwise specified. Pregnant women may be more sensitive to pesticides, underscoring the need for caution.

In addition to timing, effective pesticide application involves a series of crucial steps that ensure safety and efficacy. Spraying should be avoided on extremely hot days to prevent evaporation of active ingredients. Ultimately, if pest damage is minimal or not significant, pesticides should not be applied, emphasizing the importance of targeting actual pest problems rather than reacting to unnecessary concerns.

What Is The Threshold For Soybean Aphids?

El umbral del pulgón de la soja es de 250. Durante la etapa vegetativa tardía hasta R5 de la soja, el umbral de tratamiento es de 250 pulgones por planta (promedio del campo) con 80 plantas infestadas y poblaciones en aumento. En SDSU, recomendamos utilizar este umbral o el método de escaneo rápido. Aunque los 250 pulgones por planta no representan exactamente el umbral económico, es más conservador. Este umbral es crucial para determinar cuándo aplicar insecticidas, actuando como un umbral de acción fijo, al contrario de algunos umbrales más flexibles para otras plagas.

La soja es susceptible a daños por pulgones desde R1 (primer florecimiento) hasta R6 (semilla completa). El pulgón de la soja, Aphis glycines, es una plaga seria en el norte de Estados Unidos. Se aconseja seguir el umbral económico basado en 250 pulgones por planta cuando al menos 80 plantas estén infestadas y las poblaciones en aumento. A pesar de las fluctuaciones en los precios de la soja, el umbral de 250 pulgones se ha mantenido vigente. Para niveles de pulgones por debajo de este umbral, los insectos beneficiosos pueden controlar eficazmente la población.

Este umbral ayuda a evitar pérdidas significativas en las cosechas. Las aplicaciones de insecticidas son necesarias hasta que las plantas alcancen R6, manteniendo el promedio de 250 pulgones por planta y al menos 80 infestadas. En resumen, el umbral de 250 sigue siendo la referencia para la toma de decisiones de manejo de plagas en los cultivos de soja en estas etapas críticas.

How Long Is Aphid Season?

Aphids are common garden pests that typically appear in mid-summer and persist through fall, often causing severe damage if not managed. They reproduce rapidly, generating multiple generations within 20 to 40 days. Some species, such as cabbage aphids, mate in autumn and lay eggs that overwinter. In spring, these eggs hatch, and newly emerged aphids feed on tender foliage. As the season progresses, foliage becomes tougher, yet aphids continue to proliferate, predominantly as females, leading to the birth of many generations in a single season.

Nymphs reach maturity in about a week and can reproduce within four to ten days. Aphids can be found year-round on various plants, surviving between growing seasons on weeds and volunteer crops. Their lifecycle allows them to thrive in various conditions, making early identification and management crucial to prevent infestations.

How Many Aphids Are In A Soybean Plant?

The economic threshold for soybean aphids is established at 250 aphids per plant, with 80% of plants infested and populations on the rise. This threshold is derived from extensive university research. To assess whether treatment is necessary, thorough scouting is crucial, specifically by counting aphids on 20-30 plants across the field, focusing initially on the undersides of leaves. Note that soybean aphids have a heteroecious holocyclic lifecycle, typically overwintering as eggs on buckthorn.

These eggs, well-adapted to cold with a mean supercooling point of −34 °C, are located near buds and within branch crevices. Under favorable conditions, aphid populations can grow swiftly; counts have reached as high as 13, 000 per plant. It is essential to include both winged and wingless aphids in counts while excluding dead aphids or look-alikes. The recommended action threshold applies until plants reach the R6 growth stage, at which point averaging 250 aphids per plant, with at least 80% infestation, indicates the need for intervention.

Furthermore, when examining the potential for damage, research suggests that populations need to exceed approximately 485 aphids per plant to note measurable harm. Predator species, like the Asian lady beetle, can help manage aphid populations naturally. Overall, consistent monitoring and appropriate intervention based on these thresholds are paramount for effective soybean aphid management.

What Do Aphids Hate The Most?

Aphids, small pests that suck sap from plants, can cause significant damage in gardens. To deter them, certain plants with strong scents can be beneficial. For instance, lavender and wormwood (Artemisia absinthium) are known to repel aphids due to their potent aromas. Fennel (Foeniculum vulgare) not only attracts hoverflies, which prey on aphids, but also has a smell that aphids dislike. Garlic and onions are particularly effective; a homemade spray made from these can be used on affected plants.

While aphids are drawn to camellias, dahlias, roses, and citrus plants, they tend to stay away from aromatic herbs like dill, oregano, sage, and thyme. Additionally, banana peels can repel aphids when finely chopped and placed around plants. Other herbs like basil, chervil, and cilantro also help combat aphid infestations with their strong scents. Incorporating these plants into your garden can enhance flavors and provide natural pest control, helping to keep your plants healthy and free from aphids. By understanding which plants repel aphids, gardeners can create a more resilient and flourishing outdoor space.