How To Predict the Date of An Insect Outbreak

Have you ever heard someone say, “After a mild winter, insects will hatch early?” Is this a gardening myth? Can scientists forecast when particular insect will emerge? See the answers below!

Idaho State Department of Agriculture Entomologist Paul Castrovilla points to Phenology. The study of relationships between weather and biological activities, it is also known as the Degree-days Model (DDM).

When Insects Make Their  Appearance: Insects are cold-blooded. Their development is linked directly to external temperatures. Each requires a defined amount of heat accumulation to reach life stages like egg hatch or adult flight.

Degree-days (DD) mean a measurement of heat units calculated from an average daily high and low temperatures.  DD tell us how many heat units useful for a specific insect’s development have accumulated. In the lab, researchers determine a base and an upper threshold temperature for each species. The insect will eat and mature during this range. According to Dr. Castrovilla, base thresholds are typically set from 40 to 50 degrees F.

Example of threshold list at http://uspest.org/wea/weafaq.html

You can easily calculate Degree-days using the following formula:

[(daily maximum temperature + daily minimum temperature)/2] – baseline temperature = # DD for that day.

Accurate calculation of degree-hours over many days requires a record of hourly temperatures and is complex for a number of reasons. 

The Integrated Plant Protection Center Phrenology Site Home Page

Make Your Own Science-Based Forecast:The public is welcome to use a free web site to forecast an insect or disease in a matter of seconds.  Hosted by the University of Oregon, The Integrated Plant Protection Center combines US weather and climate data (29,000+ locations) with 110 plant pest and disease models. 

Example of DDM results for codling moth at Nampa Zip Code

The above image is a table forecasting egg hatch dates every two weeks from May 17 to July 23. Dr. Castrovilla cautions that the DD Model is not 100% precise, but can predict a date within three to five days.

Accumulated DD help in timing crop scouting events like placing pheromone-monitoring traps. That helps predict the best timing of pest management. The DDM is a useful tool in predicting when a destructive pest is likely to occur. It is also helping to identify when beneficial insects are at dangerously low levels.

To answer our original questions, it is a fact bugs will develop earlier if spring temperatures warm up earlier than normal. Few insects develop in Idaho when the temperature is below 41 degrees F. Used in combination with scouting and pheromone traps, the DDM helps determine treatment timing for fields and back yard gardens alike. That can protect crops, save money, and minimize negative effects on the environment. To be notified, Sign up for PNW Pest Alerts  

Other related resources:

"Degree day Models." How to use various models to calculate Degree-days. Washington State University. Link: http://jenny.tfrec.wsu.edu/opm/displaySpecies.php?pn=-50 

"IPM Methods:  Determining Treatment Timing Using Degree Days and Insect Phenology Models." The focus is on orchards. University of Utah. Link: http://www.intermountainfruit.org/ipm-methods/treatment-timing

"Research and IPM Models: Insects, Mites, Diseases, Plants, and Beneficials." A long list of insect thresholds. University of California. Link:http://ipm.ucanr.edu/MODELS/index.html 

5 Steps to Create a Pollinator Paradise in Your Own Back Yard

There are simple steps anybody can take to make their own backyard more friendly to pollinators.

Why should you create a pollinator’s paradise?

In short, some pollinator populations are currently under threat, especially bees. Pollination is vital to our food supply and ecosystem. We can all be part of the solution with a few simple steps!

One: Thoughtfully plant a variety of native flowers and plants.

Planting native and non-invasive plants is key. There are many species of invasive plants which have a negative effect on our ecosystems. When possible, invasive species should be identified quickly and removed. Always check your labels and ask for scientific names of plants to be sure you have native varieties. Invasive species out compete and overgrow native plants, and are often introduced to landscapes as ornamentals. Some examples of invasive species to watch out for in Idaho might be purple loose-strife or salt cedar. Learn more about invasive plants here.

When it comes to flowers, it is also best avoid wild flower mixes.

Tip: Look for flat faced flowers, rather than ruffled, double layer petals, as these are more approachable to bees and butterflies.

Your thoughtful planting should consider visual impact on pollinators. It might be good idea to choose an area specific to your pollinators, and plant a swath of plants there. Or, paint the whole yard in flowers and native plants! As long as bees, birds, moths or butterflies can see your blooms easily, they’ll stop by. Be sure to plant a variety of plants, so that your flowers do not bloom all at once. This provides pollen to bees and butterflies for a longer period of time, ensuring they have food for the duration of their lifespan.

Tip: Variety can apply to color, species, shape, height, and more! The more options pollinators have, the more likely they are able to find something they like, at any stage of life.

Two: Provide water for pollinators.

Birdbaths and water features (in every season) are great for birds, bees and butterflies. It’s important to monitor standing water, especially during the warm mosquito breeding season. Be sure to change out water in birdbaths 2-3 times a week. More details here.

Three: Create spaces for shelter.

Bees need spaces to create their homes, whether it be up high or down low! Be sure to leave ground space as native bees are solitary and dwell near the ground. Nesting sites might include dead wood or even messes of twigs and grass on the ground. These can serve as habitable spaces for bees, and even provide overwintering protection. Another consideration is mulching. If there is too much mulch, bees are unable to penetrate the surface for shelter on the ground. Tip:Leaving bare ground or using leaf cuttings or compost in a lighter layer will provide access and protection.

Four: Feed the birds, bees and everything in between.

Provide seed for birds by leaving seed heads and stalks intact for habitat and food to birds and overwintering insects.

When planting, include a few plants which support larvae and adult insect pollinators. It is always best to consider the lifespan of insects and other pollinators, as they may have a food source for one stage of life, but not another. For example: monarch caterpillars only eat milkweed. Without this food source, there is no butterfly to become a pollinator! Here's how to optimize your yard.

Five: Maintain your pollinator garden.

Weed your garden by hand often. Limit your use of pesticides. Pesticides and herbicides can end up killing off beneficial pollinators or insects that are vital pest controllers themselves. In the end, it is best to use as little pesticides or herbicides as possible. Instead, work toward maintaining your soil, and creating a healthy landscape overall, as this is the best way to keep pests or weeds at bay.

Tip: Add compost in the spring, but remember to leave room for ground dwelling bees. Plant species which require less water together. If plants require more water, group them together so they can be watered efficiently.

There are so many approaches you can take to make your backyard pollinator preferred. Here's some links:

Bee Habitat - UIdaho Extension
Idaho Pollinator Protection Plan

 Choose one, and get started today!

Unconventional Beneficial Garden Insects

We all enjoy being outside and, in our gardens, whether it be a vegetable or flower garden. Insects are a necessary part of those gardens,  through pollination or predatory instincts. But all too often we are quick to lump a majority of insects into the “harmful” insect category without really knowing the full story behind their roles in the garden.

Insects like the lady beetle and bees are well known for their benefits to the garden landscape. But did you know wasps are also beneficial to our gardens? Certain wasp species have been proven to hunt down pesky insects and remove them, thus helping the overall health of the garden. 

Mantids are also a great predator for your garden. With over 2,000 species found worldwide, these great hunters are also non-discriminate hunters and have been seen killing many pests like grasshoppers, moths, and flies. 

Another beneficial insect is the European earwig. While some people consider the earwig a pest in their garden, they can actually be beneficial to the overall balance of the garden.They are omnivore, eat leaves or petals from plants,and will eat lots of insects as well. The earwig is nocturnal, so it eats at night.

We have all experienced spiders in the gardens. There are many kind of spiders that are extremely beneficial such as the harvestman spider, also known as a daddy-long-legs. These helpful hunters help keep down the overall populations of a myriad of harmful pests in and around your garden. Pests such as aphids, slugs and other spiders have been shown to be controlled via the harvestman spider.

So maybe next time you’re out in your garden, don’t be quick to judge these pests and allow them to do the dirty work for you.

Codling Moth Control for the Small-Scale Fruit Grower

Of all of the fruit I have grown in Idaho, my favorite is the apple - not just any apple, a 'Criterion' apple picked fresh off the tree. Biting into one of these juicy, bursting with flavor apples is an orchardist’s delight.

Ironically, for any orchardist, commercial or small- scale operations in which this blog is dedicated to comes with a cost. And for many of those seasoned apple growers, significant cost of time, energy and resource is essential for the perfect marketable fruit. Ideal size (Goldilocks proportions), right color, superb taste and no blemishes. Now if we were living in the Garden of Eden, no problem, but we do not, so comes the consequences of a need for disease management, climate control, soil balance, branch and trunk care, and the dreaded pest control. 

For this article, I am only going to address pest control: one pest in particular that stands head and shoulders of all the other apple pests, the Codling Moth. This moth is a member of the Lepidopteran family Tortricidae. Interestingly, codling means “an unripe, half-grown apple”.  Now add a small worm to this scenario and you have the perfect storm of total destruction of a normal apple. And, just as one perfect apple can bring delight to the dedicated orchardist, it can also bring a grown man to tears when he discovers as he bites into that prospective delicious apple that a black headed cream-colored worm has riddled his sweet meal with several blackened distasteful tunnels…worthless to the core! 
For the untrained eye an outward examination of the suspect apple may puzzle the human consumer for even though many apples may bare the evidence of the unwanted worm that stings and eventually penetrates the skin of the apple many worms find it more convenient to enter through the “calyx end” of an apple. 
Because these worms have such a voracious appetite for apples, the small-scale fruit grower may become discouraged and find it not worth the effort to put up with these pests and so depend on the fruit stand or grocer to be their provider of these sweet worm-less treats. But for the fruit grower who holds to the tenants of religiosity, tenacity and creativity… and who has a plan in place (while these moths are in hibernation) there can be hope and there can be success! One educational source that has done extensive research on the control of the codling moth is Washington State University Research and Extension Services. 
  
 Several practical approaches starting with a better understanding of the life cycle of the codling moth can be helpful in winning the battle of the worm. WSU’s website has numerous charts ranging from life history of the moth to the pesticide spray schedule when the moth is most active throughout the year.  I have in the past used my own method of monitoring moth activity through the use of a molasses-based milk jug traps. I found at a local organic nursery  who recommends this method along with some other valuable advice using a more “organic approach”.
                                  
This is a key component of worm control in your apples. The idea is to know exactly or at least within a couple of days when the moths are on the move and are ready to lay their eggs on strategic apple tree locations to raise their offspring. 
What I like about this website is they take on more of a biological approach in controlling this moth by using pheromone traps and parasitoids I have had little success with these methods but have found a product named Spinosad to be fairly effective if used appropriately with the spray schedule for this area. I have just recently signed up online for the Pacific Northwest Pest Alert Bulletin. I highly recommend this site if you are really committed to being timely with your spray routine which could be several times throughout the life season of the moth.  As mentioned, Spinosad is my pesticide of choice and has some interesting history. In 1982, a distinctive soil dwelling bacterium called Spinosad was discovered on this Caribbean island. Spinosad has become a unique pesticide used in organic gardening.  This year I will be adding another product that meets OMRI standards, an all seasons horticulture oil with Spinosad. This product is considered an excellent fungicide, miticide and pesticide that can be used within 24 hours of harvest. 
            
The above links have some excellent additional advice on how best to control this nasty moth’s offspring appetite so we gardeners and orchardists can better reap the benefits of our fruit tree husbandry. 

Here is wishing you a juicy worm-free apple of your choice this summer. (even though Criterions are the best!) 

Raised Beds for Your Gardening Ease!

Wouldn’t it be nice to work in your garden on those beautiful sunny days without your back or knees giving out?

Building raised beds is a simple DIY project that could relieve your nagging pains, as well as enhance your garden experience and beauty.

In just a few hours, with a quick trip to your local home-improvement store or lumber yard, you can have elevated raise beds ready for your next planting.

Keep reading for a supply list and tips on planning and building raised beds.  You will also find information on soil selection and planting.

1. Planning: Determine where to install the raised bed(s).  Look for a place where the new bed will have at least 8 hours of summer sun.      

Also, determine the desired size of the raised bed.  For width, consider what is easiest for you to reach across and for height, consider what is easiest for you to lean over, if at all.  A typical standard size is approximately 3.5' x 8.5' x 18".

2. Supply List: For a raised bed of the above mentioned dimensions, the following is needed:
Qty 2: 2" x 12" x 12'
Qty 2: 2" x 6" x 12'Qty 1: 4" x 4" x 8' Corner Post
Large box of Deck Screws #8 x 3"
Tools: miter saw or compound saw; drill bits for pilot holes; screwdriver for drill bit

3. Assembly: 

a. Cut the 12'-length boards to 8.5'; leaving 3.5' for the end piece.
b. From the corner post, cut four 18" sections that you will attach the other boards to.
Note: If you do not want to deal with the assembly process with the 4" x 4" posts, you can try slider connectors or brackets.  With the connectors, you can just slide your board through and use deck screws to secure.

4. Placement: Once the bed is assembled, place it in the desired location in your garden.  If you are placing it in an area that still has sod/grass, a good option is to lay old cardboard boxes down first.

5. Soil Preparation: Compost mixture you’ll be putting inside.  A great place to start is a mixture of 30% compost and 70% topsoil.  To calculate the amount of mixture for the above bed dimensions:

Multiply 3.5 x 8.5 x 1.5 to get 31.25 cubic feet of total soil mixture.  As 27 cubic feet equals 1 cubic yard, it is safe to get 1 yard of topsoil along with 1/3 of yard of compost.  Allow a few days for the soil to settle.  Happy Planting!

Steps to a Healthy Lawn and controlling Weeds

The first step to having a healthy and attractive lawn and controlling weeds is choosing a grass variety best adapted to your life style and available resources. Factors to consider would be high traffic, shaded and sunny areas, type of soil, available water and amount of time available to care for the lawn.

Irrigate properly to help reduce annual weed infestation. Light frequent irrigation encourages weed seed germination, even if a pre-emergence herbicide has been applied. Water 1- 1.5 inches per watering. Do not water again until you see signs of wilt. Turf will also turn a shade of blue green when it is water stressed. The best time to irrigate your lawn is between 10 pm and 6 am.

Mowing The preferred mowing height for all species of grass is 2 ½ - 3 inches. The minimum height that any lawn should be mowed is 2 inches. Mowing to heights less than 2 inches results in decreased drought and heat tolerance plus higher incidences of insect, disease, and weed problems. The seeds of some weeds require high light intensity to germinate. The shaded environment near the soil surface in high mown lawn helps deter weed germination. Mow frequent enough that no more than one third of the grass height is removed at any single mowing. If the mowing height is two inches. the grass should be mowed when it is 3 inches tall. If the mowing height is 3 inches, it should be mowed when it's about 4 inches. Keep your mower blade sharp to avoid shredding and fraying leaf blades. Grass clippings should be allowed to fall back into the yard to provide natural nitrogen.

Pre-emergence herbicides. A Pre-emergent is activated in the top layer of soil, where the weed seeds sprout, and by design it stops the plant from growing. A pre-emergent is NOT effective once the weeds are showing. Spreading out the herbicide so that it is evenly distributed is critical. It must also be watered into the soil within the appointed time period. The soil must remain undisturbed in order to maintain the barrier. A pre-emergent has to be replaced, or replenished. Pre-emergence should be applied two to four weeks before when seeds germinate in mid March to early April depending on weather. Warm moist springs cause earlier germination The temperature of the soil ( 55-60 degrees) as it starts to warm up in the spring, will be the primary indicator of the pending arrival of various weed species. With normal weather patterns, pre-emergence herbicides give good to excellent control of crabgrass, foxtail, and barnyard grass. Do not over seed into areas that have recently been treated with pre- emergence.

Post- emergence herbicides. Perennial broadleaf weeds can be controlled by post emergent herbicides. It is important to properly identify the weed before choosing an herbicide. Some common perennial broadleaf weeds in lawns are dandelion, field bindweed ( morning glory) White clover, curly dock, ground ivy, Canada thistle, broad leaf plantain, buckhorn plantain and yarrow. The best time to control perennial weeds is in late summer or early fall when weeds are preparing for winter.

Core cultivate (aerate) the lawn at least once a year to reduce compaction and to control thatch.
Fertilizer may be needed if lawn has poor color and vigor, doesn’t recover from traffic or has more weeds present. Nitrogen is the most important nutrient for lawns. Do not use Phosphorus or Potassium unless a soil test indicates it is needed. Cool season grasses should be fertilized in fall, late spring and little in the summer. Warm season grasses should be fertilized late May, June, avoid late summer and fall.

Check out the resources below:

http://extension.colostate.edu/topic-areas/yard-garden/control-of-annual-grassy-weeds-in-lawns-3-101/

http://www.uwyo.edu/barnbackyard/resources/weeds.html

http://web.cals.uidaho.edu/idahogardens/2012/08/weeds/

Crab Grass	White Clover
Field Bindweed	Henbit
Dandelion	Broadleaf Plantain
Buckhorn Plantain	Canada Thistle

Spring Soil Prep - What you can do Now! (or as soon as the ground thaws :>)

The best way to begin preparing your soil is with a soil test. 

Your local University of Idaho Extension office can help you with this. This test is a great place to start because it tells you what to add to your soil to help your garden perform better. 

soil sample probe

Organic soil amendments also provide an important source of nitrogen for your plants.  Till or turn under with a spade 3-4 inches of compost into your soil at a depth of 6-8 inches and rake your bed smooth.

With a soil sample probe, the task is much  easier... and worth the cost - since you'll probably check your soil many times over the years.

This video shows how to gather your soil sample.

The most important thing you can do for your garden’s soil is to add organic matter. Organic matter aids in drainage and minimizes soil compaction, which reduces soil oxygen.

When choosing an amendment, consider carefully what you use. Animal based products and bio-solids are high in salts and heavy metals which build up in your soils. Consider using well aged plant based compost instead.

Now...check your plant temps, and frost days and...enjoy planting!