Why do aphids show up on a plant? It’s a plant nutrient imbalance
“Insects behavior is deliberate and designed to eliminate weak, unformed, nutritionally deficient, unbalanced plants” Dr. Arden Anderson
The turgor pressure imbalance that develops in the plant causes exudates to come to the leaf surface. Those exudates include simple sugars, free nitrogen and simple amino acids. Because the exudates are present, aphids and leafhoppers show up on a plant for a free lunch
“Insects attack only sick plants having incomplete proteins, free or fragmented nutrients which insects are able to digest” Francis Chaboussou, Paris, 1985
Aphids do not suck!!!
Aphids only feed from a plant that has a turgor pressure that forces exudates to the exterior of the leaves. The strongest muscle in the aphid is the mouthpiece that attaches to the plant.
Soybean aphid 2005 field trials - Levels of infestation are related to plant health
The following is a review of what I found in soybean and edible bean fields in three states. This analysis was done in organic soybean and edible bean fields, conventionally grown soybeans and round-up ready soybeans. This includes field tests in Wisconsin (Dane County), Illinois (Dekalb County) and Michigan (Central and the thumb area).
The population of soybean aphids varies considerably from field to field, whether it is soybeans or edible bean varieties. Populations from zero to 5000+ aphids per plant were observed in soybean and edible bean plants the week of Aug 1, 2005. The one common relationship to the levels of aphid infestation appears to be plant health. Generally, we relate plant health to Sap ph and dissolved solids (Brix).
Here are my findings:
Plant Readings Insect population
SAP ph BRIX aphid count/ plant
______________________________ ___
6.2 ph 9.5 0-10 aphids
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5.8 ph 8.0 50-100 aphids
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5.6 ph 200-500 aphids
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5.4 ph 5.8 2000- 3500 aphids
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5.3 ph 5.7 over 3500 aphids
As I will detail later, the healthiest bean plants will show a sap pH of 6.2-6.4 and the Brix at 12-14. The lower the sap pH, the less healthy we find the plants because we relate the lower sap pH to low cation levels (calcium, potassium, sodium and magnesium). The lower the Brix, the lower the dissolved plant solids. Note that the plants that are closest to these parameters are the ones with the fewest aphids in my field scouting trials.
How do you make plants healthy?
Biologically active soil is required to maintain healthy plants. A six to seven year soil-building program with a sustainable nutrient plan can be used to build up soil and sustain a healthy state. Healthy soil generally translates to healthy plants. It is believed that the more biologically strong the soil, the higher the level of natural disease resistance. It is believed that healthy plants have systemic acquired resistance (SAR). If stress conditions affect healthy plants, corrections can be made with a foliar spray program to compliment a soil nutrient program. A common cause of plant stress is extremes in weather (too hot, too cold, too wet, too dry).
Growers that have been doing a foliar nutrient program including fish hydrolysate, biologicals, trace mineral pack, K sulfate and calcium foliar can feel comfortable that they are going a long way to keeping insects in check. Insects (aphids, bean leaf beetles and leaf hoppers) are generally the vectors for plant diseases. Foliar feeding for plant health, for suppressing insects and suppressing pathogens and viruses all simultaneously will be very profitable.
How do we identify healthy plants?
Three methods are known to determine if a plant is healthy: pH, Brix and Electric Conductivity.
Listed below are the parameters that determine a healthy legume (soybeans, alfalfa, peanuts and green beans). When these levels are met, there should be no plant diseases and no insects on a healthy plant:
Sap pH............................ ..... 6.2 - 6.4
Brix.......................... ..............13 - 20
Electric Conductivity (EC)...12,000-16,000
Sap pH relates to the acid/base balance. If the pH is low, say 5.5-5.8, the plant has a short fall in cations (calcium, potassium, sodium or magnesium). If the ph is high, the plant is low anions ( nitrate nitrogen, phosphates, sulfates or trace minerals).
Brix shows the dissolved solids in the plant. The higher the dissolved solids, the healthier the plant. If Brix is low, even after several hours of sunshine, some element(s) are missing in the photosynthesis factory. Ions, if present, have not been "complexed" into sugars or proteins.
Electric Conductivity – A high energy field in a plant is a natural defense for invasive forces (insects and plant pathogens) A high plant energy field is a natural defense for invasive forces of insects and plant pathogens.
Field Testing equipment
1- Testing for SAP pH
Using Litmus paper – cut open succulent plants and dip the paper on the stem. Do not use a garlic press to squeeze juice. This will give a false reading because of the chlorophyll that is placed on the paper.
Using an electronic pH meter – proposed procedure: cut leaves and stems into two-inch lengths, place in a garlic press or pliers and squeeze juice on to the eye of the meter. Read digital number.
2- Testing for Brix
It’s suggested to use a standard refractometer. Cut plants and stems and squeeze juice onto the glass. Use the chart to determine the Brix level for various species of plants
3- Testing for Electric Conductivity (EC)
Measured with the Cardy Twin EC Meter, EC indicates the level of simple ion uptake into the plant sap.
With a low Brix crop, if sap EC is too low, the elements are not being made available to the plant. If sap EC is too high, elements or ions are not being "complexed" and ions such as nitrate nitrogen may be at excessive levels.
Steps to Promoting the Healthy Plants
Step 1 Seed treatment- Mycorrhizal Fungi treatment (Myco Seed treat), Rhizobium inoculant
Step 2 Liquid plant starter program – Nutrient management plus Insect suppression
Step 3 Petiole Analysis- determine the health and deficiencies of the growing crop. Do this by July 10-15
Step 4 Foliar program-Soybeans
Recommendations – Feed at 3-6 inch tall if plants are stressed
Feed at R-1, this is key to SAR
Example of a foliar program
Soybean foliar program
2oz-3 gal Biological pack (Compost tea, AER SP1 or Liquid Bacteria)
1 gal Drammatic “ONE” Fish Plant Food
1 gal K-Sulfate
1 pt trace minerals (AgriEnergy Foundation)
8 oz Neem Blend 45 EM
3-15 gal Water
Application Rates
Organic Soybeans, Edible Bean, Green Bean Production Program
The following is information pertaining to the control of edible bean pathogens and insects. Over and beyond soil nutrition and bio-insecticides, the Dramm Liquid Fish and microbial packages are the inputs that I work with to aid in the suppression of plant pathogens and insects. For the foliar feeding of soybeans, the three key stages that I recommend foliar feeding are the third trifoliage, R1 and R 5-6 stages. These may vary on the level of infestation.
Insect suppression proposed foliar applications
Third Trifoliage
Proposed Formula-per acre application
1 gal Drammatic E (use to adjust tank mix ph to 5.8-6.0)
8 oz Neem Blend 45 EM - (must have .05 -.25% in the formula)
2 oz-3 gal Biological pack (Compost tea, SPI or Liquid Bacteria)
2-18 gal water-
optional Mycotrol O *
optional- soybean aphid or leaf hopper control: adding 2-4 oz garlic oil to the formula will reduce the aphid populations as they are moving into the area. Because aphids and leafhoppers identify plants via UV censors, the garlic oil sprayed on plants will deflect UV and insects will not be drawn to the sick or stressed plants for up to two weeks.
This mix must have a ph of 5.8-6.0 for maximum results. For best results the pH of the tank mix should be as low or slightly lower than the plant SAP pH. An excessively lower tank ph may destroy the microbial life of the foliar spray and a higher ph will reduce the uptake of the foliar application in the plant.
The R1 (early flower) stage- Foliar feeding is very beneficial because of the high demand for phosphorus. This will maintain or increase the brix levels at this time. The fish hydrolysate will improve the phosphorus demand because of the large amount of phosphorus in the foliar fish.
Proposed Formula-per acre application
1 gal Drammatic E (use to adjust tank mix ph to 5.8-6.0)
8oz Neem Blend -(must have .05 -.25% in the formula)
2 oz-3 gal Biological pack (Compost tea, AER SP1 or Liquid Bacteria)
2-18 gal water
optional- soybean aphid control or leaf hoppers: adding 2-4 oz garlic oil to the formula will reduce the aphid populations
Plant stress at R1 stage through pod fill:
Plant flowering requires large amounts of phosphorus, any plant phosphorus short fall in the plant will put the plant in stress, lower the Brix. This generally is the time that the producers will also witness the buildup of soybean aphids and leafhoppers. If the growers have used a liquid starter program (a program high in carbon including complex sugars), the aphids will generally be controlled until the later phases of plant development.
R5 to R6 stage (late pod set and early pod filling)
Proposed Formula-per acre application
1 gal Dramm ONE Liquid Fish (to adjust tank mix ph to 5.8 6.0)
8-12 oz Neem Blend 45 EM -(must have .05 -.25% in the formula)
1 gal QA Bio Special or AER SP-1
2 oz Citrex – labeled for white mold suppression in Europe
2-18 gal water
optional- soybean aphid control or leaf hoppers: adding 2-4 oz garlic oil to the formula will reduce the aphid populations
Foliar feeding for bean leaf beetle
Foliar OPTION 1- third trifoliage
Many growers have not had the insect pressure in the past to be proactive on the front end. Generally the first sign of insects is when the adult beetles begin feeding on the newly emerging soybeans. This is the prime time to suppress the advance of the beetles. Any larva that are feeding on the plant roots will pupate and emerge in July. It’s at this time that quick action must be taken.
Foliar OPTION 2- R1-R3 stage (early flowering)
The emergence of the beetle and the flowering of the soybean plants are simultaneous over that two week period in mid to late July. Without suppression of the beetles both yield loss and bean quality will be a byproduct of the insect pressure.
Product descriptions
Neem Blend 45 EM: The foliar treated leaves will absorb and therefore contain concentration of azadrachtin, the active ingredient in the botanical neem oil (Neem Blend 45 EM) for up to 15 days. I have witnessed that the chewing or sucking insects will then be reduced by up to 80% in 4-5 days. The neem oil is a growth regulator. The insects that do survive, generally, will not produce any young or mature. This includes the leaf hopper, alfalfa weevil, bean leaf beetle and aphids. From the good side, the beneficial insects are not eating the plant (herbivores) so they will not be affected according to Doug Murray, IPM Specialist, Paw Paw, Michigan.
Mycotrol-O*: The addition of Mycotrol-O to the starter program will inoculate the soil with additional Beauvaria Bassiana, a fungi that attacks insects. The unique thing about Mycotrol O is that it reproduces best in wet or moist conditions. I began using it in combination 6 years ago. The reason for adding it to my insect suppression program is that it is the first bio-insecticide that works better in wet conditions.
Neem oil, Garlic Oil, Citrex and Mycotrol O are EPA registered bio-pesticides.
Smaller scale, garden formula
Foliar nutrient package plus insect suppression
To fill 3 ½ gal back pack sprayer
2.75 gal Water
1 pt Drammatic “One”
1 pt AER SP-1
1 oz Magnesium Sulfate (Epsom salt)
1 pt K-Sulfate
1 pt Chilean Nitrate
1 cup AER Organic Foundation
4 oz Neem Blend 45 EC (neem/karanja emulsified)
1 oz Citrex (Add Citrex last to the tank mix)
Note : K-Sulfate, Chilean Nitrate and Org. Trace Pack can be pre-blended
Caution: Mixing any other of the biologicals prior to application is not advised
Formulas used by Reg Destree, LaCrosse, WI 54601. reggieveg@charter.com 608-785-2790
Plant Tissue Testing
Introduction:
This method of plant sap analysis is relatively new. Sap is squeezed from the fresh plant tissue and analyzed for Brix, pH and EC. Data collected can be used as a tool in fertility management. Please note that the information contained here is preliminary.
Although research continues in the area of plant sap analysis, little interpretation data is available. Over a period of time, it is recommended that a grower establish his own data, based on analysis results, fertilizer applications and crop response.
REVIEWING PLANT TISSUE TEST RESULTS
Apply the foliar spray to a test plot. After a minimum of two hours of sunshine, test the Brix of the treated plants as well as some of the untreated plants. If the test area is at least 2 Brix higher than the control area, the spray was effective and can be applied to the whole field.
This information and Chart are reprinted from Pike Agri-Labs June 2, 2006
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01-18-2013, 03:24 AM
