Organic blueberry spray guide from NCSU

Bill Cline, NCSU extension plant pathologist based at the Horticultural Crops Research Station in Castle Hayne, NC, has spearheaded the development of an organic IPM program for North Carolina blueberries. Together, Bill and I have produced the 2011 Organic Blueberry Spray Guide. This document lists organically acceptable practices and management tools for key blueberry pests in North Carolina. This document is only intended for use by North Carolina growers. If you are interested in organic blueberry production information and are from another state, contact your local cooperative extension agent (see here to connect with your location extension personnel).

As with any "spray program", bear in mind that not all treatments are needed at each location. This document is not a schedule which should be followed, but instead a guide as to what pests may occur and how to manage them if present. Scouting & monitoring should be the keystone of any IPM program, and treatments should only be made if economically significant populations are present.

More information
Organic Blueberry Spray Guide - Bill Cline & Hannah Burrack

Grape root borer captures in NC vineyards

Mating pair of grape root borer moths (female, left; male, right).  Photo: H C Ellis, University of Georgia, Bugwood.org

Two North Carolina vineyards have reported grape root borer (Vitacea polistiformis) trap captures in the last week.  Both vineyards are in the Yadkin Valley, where many of our wine grape growers are located.  If these places are capturing moths, they are likely active in other vineyards in the area.  Many wine grape growers do not monitor for grape root borer, so we do not have a good sense of how wide spread they are NC, but they are capable of infesting grapes throughout the state (both bunch/wine grapes and muscadines) and occur throughout the eastern US, from Florida through Ohio.

Grape root borer injury.  Photo: James Solomon, USDA Forest Service, Bugwood.org

Grape root borer larva.  Photo: Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org

Grape root borers are potential devastating pests.  As their name suggests, the larvae of grape root borers feed on the roots and crowns of vines.  Like related species (ie. raspberry crown borer), larvae may live for 1-2 years, longer in northern latitudes, and shorter in southern.  According to Tennessee entomologists, larvae there take 22 months to develop on average.  This same Tennessee factsheet has a great overview of grape root borer biology.  Briefly, egg laying begins about 8 days after emergence, and the eggs take 14 days to hatch.  Eggs are laid at the soil surface.  These newly hatched larvae are the most easily controlled life stage, and chemical treatments (if used) are targeted to them.  Once the larvae enter the roots, they are very difficult to control.  Adult control is also impractical, because the moths do not feed on grapes and therefore would not contact insecticides applied the crop.  Adult moths emerge and lay eggs over a relatively long period of time as well, further complicating management. 

Much of this difficulty arises from the materials registered against grape root borer.  Only one conventional insecticide, Lorsban (chlorpyrifos) is registered.  Lorsban has a long pre harvest interval in grapes (35 days in bunch grapes).  Because moths may continue to emerge until fall, this application timing may be too early in some cases.  Ideally, a material which could be timed to moth trap captures would be more useful.  Identifying an alternative to Lorsban with a shorter PHI is a high priority IR-4 project, but the long life cycle of this pest slows this process.  Non chemical management tools are also available.  Entomopathogenic nematodes and pheromone-based mating disruption (essentially confusing male moths) have shown promise experimentally, but neither have been brought up to commerical scale.  Cultural control by soil mounding (in early July or the start of moth emergence, whichever comes first), can also reduce moth numbers.  Soil mounded around the base of vines creates a longer distance for emerging moths to travel, and they die before reaching the surface.  See the Southern Regional Small Fruit Consortium's Bunch Grape IPM Guide for specifics on treatment options.

Monitoring

Pheromone lures attractive to male moths can be used to detect adults, and these are traps growers have caught moths in this year.  Several trap types can be used in combination with these lures (typically rubber septa impregnated with pheromones), but the easiest to use is probably the bucket trap.  These traps are available from several suppliers (some are listed below).

 

Grape root borer monitoring trap.  Traps are baited with a pheromone lure attractive to Photo: Insect pests of grapes in Florida

Although the grape root borer pheromone is relatively specific, one related species can also be attracted to the traps.  The squash vine borer (Melittia cucurbitae, below) is easily distinguished from grape root borer.

Squash vine borer adult are orange rather than yellow/brown like grape root borers and have more bristles on their rear legs.  See here for another useful image.  Photo: Purdue University Cooperative Extension

In addition to traps, which attract male moths, growers should also scout for pupal cases under the vines.  This will provide a better sense of the total moths present in the vineyard, as traps may pull males in from nearby plantings or wild grapes.  Other states have used pupal case counts to develop treatment thresholds.  Kentucky entomologists recommend treating when 5% of vines have pupal cases present.  Thresholds are an important component of an IPM program, because there are consequences (economic, environmental, etc.) to each management decision, and unnecessary treatments should not be made.

Trap sources

Great Lakes IPM

Trece, Inc.

Gempler's

ARBICO Organics 

Flue Cured and Burley Tobacco Information Guides online

The 2010 editions of the Flue Cured and Burley Tobacco Production Guides are available online through the NC State IPM Program. These guides are also available in hard copy form from county extension agents and NCSU tobacco specialists. I have several copies of both on hand and always carry at least one in the truck while in the field.

Because the guides are revised once a year, some information may change before the next revision comes out. The biggest change in insect management for 2010 not reflected in these guides is the recent federal registration of Coragen (a newer insecticide from DuPont) for use in tobacco. The state labels are currently pending, and I will post again once these have been finalized. We have conducted 10 trials in the last 3 years with Coragen and Belt (another newer insecticide from Bayer with a similar mode of action) and data on how these materials compare to standard materials is in the production guides (Belt) or has been shared at grower meetings (Belt and Coragen).

Updated 4.8.2010
I also wanted to include a link to an "oldie but goodie" resource: Scouting Tobacco in North Carolina, developed by my tobacco predecessor, Sterling Southern.

Spring Strawberry Arthropod Management Reminders

No matter what the forecast says, spring is coming. Along with it, come greater management needs. Strawberries have been in the ground since last fall and are the first fruit crop harvested in spring. The cold winter has meant most of our plants have been under row cover for at least part of the winter and our arthropod (insect and mite) issues have been out of sight and out of mind.

Row covered strawberries at Vollmer Farms, Bunn, NC. Spring, 2009.

When these cover come off, the real arthropod management begins. Here are a few key steps to start the 2010 season out right (A note about pesticide recommendations):

Green peach aphid (Myzus persicae) on strawberry. Image from UC IPM.

1. Scout for aphids, but only treat if populations are high. Aphids can rapidly proliferate under row covers, but unless early spring populations are causing sooty mold build up, treatment is likely not needed. Later spring and summer populations are often kept under good biological control in NC. If aphid populations under the covers are producing sooty mold and exceed 10 aphids/newly expanded leaf on average, treatment may be justified. If systemic insecticides are your aphid management tool of choice, the time to use these is now (before covers come off). Once blooms are exposed to bees, the labeled systemic materials for aphids in strawberries can no longer be used.

Female twospotted spider mite, our most common spider mite pest in strawberries. Image from UC IPM.

2. Begin spider mite sampling. Spider mites are the key arthropod pest in southeastern strawberries. Mite activity is typically lower in winter months, but as temperatures warm, spider mites will become more active and reproduce faster. We are currently studying the impact of long term row cover on overwintering mite populations, but our working assumption is that row covers potentially increase mite populations over the winter. This winter, of course, all bets are off. It is important to track mite populations closely and be prepared to treat when they reach our recommended treatment threshold (5 mites/leaflet). This threshold is based on a random sample of 10 leaflets/acre. It is in grower's best interest to treat at threshold levels and not on a schedule basis, because virtually all of the labeled miticides have restrictions on the number of applications and/or amount of active ingredient that can be applied to strawberries per season. We want to keep as many good options in our tool box for as long as possible.

Phytoseiulus persimilis, one of the commercially available biological control agents for spider mites. Image from UC IPM.

Biological control is also an option for spider mites, but we are in the process of optimizing methods for NC and do not have concrete recommendations at this time.

I have heard a lot of rumblings about different materials being applied systemically for mites, and I want to be perfectly clear: There are no systemic miticides. None of the materials currently labeled for soil or drip applications in strawberries are either registered for or effective against spider mites. Our best chemical control for mites is over the top treatments of miticides. I also do not recommend the use of pyrethriod insecticides against mites. The pyrethriods registered in strawberries have either shown no effect in our trials or have actually increased mite populations because they are equally toxic to beneficial insects.

Strawberry clipper damage in Lee County, NC, 2009. Photo from Stephanie Romelczyk, Lee County Horticulture Agent.

3. Do not assume you will have clippers in 2010 just because you had them in 2009. I had several reports of clipper injury in 2009. We do not have a sense of what 2010 will look like with respect to clippers, but I am not recommended a preventative treatment just because damage was observed in 2009. Most strawberry varieties compensate to a certain extent for clipper damage, and rescue materials are available for clipper management. Pre bloom preventative applications may be too early to really protect plants. When scouting for clipper damage, remember, clippers only affect flower buds (as in the above photo), not leaves.

You can find more specific information about pesticides in the NC Ag Chem Manual and the Southeastern Strawberry IPM Guide.

I will post a mid season arthropod reminder for strawberries in May which will cover late season mite management, sap beetles, thrips, and the unusual occasionals we see as the weather gets warmer.

Reminder - NE IPM Berry Webinar Wednesday!

Ripening blackberries at Killdeer Farms in Kings Mountain, NC.

A reminder that the NE IPM Berry Webinar concludes Wednesday, February 17 and is open to the public. All the details can be found in my previous post. I hope to "see" you there!

VA Berry Conference Online

One the highlights of my spring meetings in 2009 was the March Virginia Berry Conference, organized by Reza Rafie and Chris Mullins of Virginia State University. Over 120 attendees from across the southeast listened to presentations on small fruit production and management. Meet the Farmer, a program that documents local farming systems, was also in attendance and assembled sections of the talks for one of their programs.



My section is about 23 minutes in, but all the segments are worth taking in if you have time.

What does IPM mean?

It's in the title of this blog and it's something I spend most of my day thinking about, but when I talk to folks outside the university system, I'm not always sure IPM is understood as well as we think it is. This year is the 50th anniversary of one of the most influential papers in entomology (and agricultural biology) and the paper that introduced the integrated management concept. "The integrated control concept" by Stern, Smith, Van Den Bosch, and Hagen was published in 1959 in the University of California journal, Hilgardia. Integrated control in this paper was defined as "pest control which combines and integrates biological and chemical control". While revolutionary for the time, this definition is somewhat limited in comparison to how we think of IPM today (it's not just biological and chemical control).

In the last 50 years, the term "control" has been replaced with "management" to acknowledge the fact that we're a player in agricultural systems, not necessarily in charge.

Other definitions of IPM include:

EPA: IPM programs use current, comprehensive information on the life cycles of pests and their interaction with the environment. This information, in combination with available pest control methods, is used to manage pest damage by the most economical means, and with the least possible hazard to people, property, and the environment.

UC IPM: Integrated pest management (IPM) is an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties. Pesticides are used only after monitoring indicates they are needed according to established guidelines, and treatments are made with the goal of removing only the target organism. Pest control materials are selected and applied in a manner that minimizes risks to human health, beneficial and nontarget organisms, and the environment.

Radcliff's IPM World: Integrated pest management can be defined as the practice of preventing or suppressing damaging populations of insect pests by application of the comprehensive and coordinated integration of multiple control tactics.

All of these definitions have the same core and get their message across with varying degrees of brevity, but maybe because I like things catchy, I found myself wanting a different way to explain IPM when I spoke to growers and the public. Last year, while driving (which I do a lot for work) I thought about the 3 word that really mean IPM to me: Minimize, Monitor, and Manage.

These broad action categories crystalize the concepts in the definitions above (and many, many others). We should first minimize the likelihood of pests (insect, disease or weed--IPM covers the whole range--it's not insect pest management!). We minimize by selecting good cultural practices: resistant varieties, water management, planting date, nutrition, and many others. We then need to monitor our plants, for pests and for general health. Sometimes these monitoring programs are systematic, sometimes they are as simple as walking through your feed and noticing what's going on. Monitoring also includes correct ID of pests--if you don't know what you have, you can't know what do about it! Monitoring (or knowing a pest population density) is also important when using thresholds. Typically, pest populations have to reach a certain density before you start loosing money--treating before that threshold actually costs more than the good it does. Finally, management. This is where Stern's ideas come back. Management options include biological, cultural, and chemical. As a rule chemical control should be our last choice and should be used in a way to cause the fewest additional problems.

A note on pesticide recommendations

Hands down, the most common question I am asked as an extension specialist is "what do I spray to control X?" I knew this would be the case from the get-go, and I enjoy helping growers and the public make good decisions about what, when, and how to use pesticides on their crops. That said, this blog will not be a forum for making those recommendations. Pesticide labels change frequently and vary by state. Because I don't know where you (hopefully there's a you) are from, what's available in NC may not be available or legal for your use. NC residents can refer to the NC Ag Chem Manual for recommendations for specific crops or can contact me directly for more detailed information. Interested parties outside NC are welcome to also contact me, and I will do my best to put you in contact with the right folks for recommendations in your state.