Pepper weevil pathways

Final Report for ONE13-185

Project Type: Partnership
Funds awarded in 2013: $14,914.00
Projected End Date: 12/31/2013
Region: Northeast
State: New Jersey
Project Leader:
Joseph Ingerson-Mahar
Rutgers University
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Project Information

Summary:

This project is a complement to one funded in 2012 (SARE ONE12-161) that sought to discover the route of entry of pepper weevil into New Jersey.  In the 2012 work we confirmed that the weevil’s entry point is not from farmers using Southern transplants as is commonly described in agricultural guidance documents.  Farmers here don’t use Southern transplants. We uncovered many circumstances which encourage the weevil’s spread once found in the field, but the source remained elusive.  In this 2013 project, (SARE ONE13-185), we changed focus from monitoring farm practices to evaluating the potential impact of the supply and distribution system.  We monitored for pepper weevil at or near five processing/repacking facilities, one of which has two locations.  Additionally, we placed pepper weevil traps at 25 farms, 2 greenhouses, a waste hauler, a crate supplier, a research station, a pick up point for field workers, two ethnic markets, itinerant housing areas and a municipal waste facility.  We included two tomato fields. The weevil trapping spanned seven counties (Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, and Salem).  Weevils were captured in all traps except at the crate supplier, behind a supermarket, and at one remote farm in Cape May County.  A strong pattern emerged that reveals the early season arrival of weevils in April, May and early June at the processing facilities and their nearby traps.  All other areas monitored were devoid of captures until after the first detection of the pest at the processors/packers.  Weevils appeared in pepper fields by late May, following the pests’ arrival at the processor/packer, and then continued to spread and to be detected routinely throughout the season.  Throughout the season we found them not only on cards, but on and in the fruits at all life stages.  They continued to be present even after fields were plowed under.  We observed the spread and developed an understanding of the habit of the insect here. We now can provide guidance to farmers in detection and aid growers in suppression of populations of the pepper weevil.

Introduction:

New Jersey ranks fifth in pepper acreage (3300 acres) and third in yield and value (~$33M) (Fruit and Vegetable Crops, Statistics and Rankings, 2010). Pepper weevil, Anthonomus eugenii Cano, is a primary pest in pepper production systems in the southern United States with the first known infestation occurring in Texas in 1904 (Elmore, et al, 1934).  Since that time it has increased its range across the southern United States from California to Florida and Hawaii, and is also found in Central America, South America and the Caribbean.  It is a subtropical insect that probably has co-evolved with the Capsicum species on which it feeds and reproduces.

Pepper weevil is an opportunistic insect pest that can be transported by various means to non-native regions, so that in New Jersey it is an invasive pest, as it cannot overwinter where it does not have a constant food supply throughout the year.  It has a short life cycle of 2 ½ to 3 ½ weeks.  Female weevils lay about 200 eggs, singly, in the flowers or developing fruit of peppers, creating small dark spots usually at the center of dimples in the surface of the fruit.  Upon hatching, the larvae begin feeding on the interior of the developing pepper, and thus are inaccessible to sprays.  The plant is able to recognize the damage and will abort small infested fruit.  Weevil larvae in the surviving fruit complete their life cycles within the fruit entering into a pupal stage after three larval instars.  The mature adults chew an escape hole in the wall of the pepper.

Adult pepper weevils will feed on many solanaceous plant hosts, including tomatoes, potatoes and eggplant, and many species of weeds, including nightshade, horsenettle, and jimson weed but reproduce only on Capsicum species and nightshade.

Sporadic severe infestations have occurred in New Jersey since 1957 (Ghidiu and Rabin), and anecdotal references indicate even earlier infestations.  Since 2004, there have been nearly annual severe infestations in peppers causing 5 to 80% yield loss (Pepper Pest Management Strategy Plan, Delaware, New Jersey, Maryland Eastern Shore, 2008), especially in the Hammonton area of southern New Jersey. Attempts to manage weevil infestations have largely been futile with continuing yield loss despite weekly insecticide applications.

In 2012 and 2013, two NE-SARE grants ($15,000 each) and a $6,000 award from the New Jersey Vegetable Growers Association’s Charles Maier Fund, allowed us to intensely monitor for adult weevils using pheromone traps to determine how the weevil is transported to New Jersey and once there, how it spreads from farm to farm. 

In our SARE work in 2012, pepper weevil again arrived into Southern NJ.  We discovered it in widely separated areas, and then even monitored over the winter.  We do not suspect that the weevil has adapted to the area and it is not overwintering here.  We do not suspect arrival of transplants to farms from Southern areas (Florida, Texas) to be a source.  We found weevils in a number of non-farm areas. 

Based on the findings in the 2012 work, for 2013 work, we suspected that the initiating source for pest arrival is outside the farm practices in some activity that is ancillary to the farm production.  In 2013 we monitored many areas of pepper handling that are near to pepper fields.  Included were processing plants, itinerant worker areas, ethnic markets, and a packaging supplier.  We continued to sample at farms.  Early pest arrivals to or near local processors have now been documented.  All processors included in our sampling evidenced pepper arrivals with the receipt of southern peppers.  Those willing to share information did advise of receipt of the fruits from Florida. These weevil arrivals, in all cases, preceded arrivals to farms.  The spread of weevils to the pepper fields increased throughout the season peaking in October.  In 2012 we trapped about 1,000 weevils.  In 2013, as we learned where to focus attention, we trapped nearly 21,000. As continued from last year, economic and environmental concerns remain among the farmers and IPM personnel. We now can eliminate several suspicions of route of entry, and can document potential mechanisms of spread.

Project Objectives:

The primary objective was to determine the route of entry of pepper weevil onto farm fields in New Jersey. Visual detection for the weevil via lure on tanglefoot-coated cards remained the primary evaluation tool, supplemented by scouting.  These cards are baited with a dual pheromone system.  If we can accomplish the primary objective, then we need to develop protocols for farmers to prevent or minimize the weevil’s arrival, thereby mitigating the need for pesticide control. Once the weevil arrives here, we need to develop control recommendations to avoid crop damage.

Primary targeted areas to seek out pepper weevil presence for 2013 were those non-farm entities which handle peppers or the discards external to the farm. Tracking did continue on the farms.  We intended to:

  • Document weevil presence primarily using pheromone traps supplemented by field scouting techniques
  • To the extent that cooperation of private entities is forthcoming monitor:

o   Entry points in the distribution system such as area importers, re-packers, processors

o   Waste areas, cull piles

  • Include monitoring of high traffic areas on farms known to be affected in 2012, such as:

o   packing houses

o   loading docks

o   migrant housing

Promulgate lessons learned

Cooperators

Click linked name(s) to expand
  • Bernadette Eichinger
  • Bob Muth
  • George Ruggero
  • August Wuillermin

Research

Materials and methods:

Visual detection for the weevil via, tanglefoot-coated cards having pheromone lures attached, remains the primary evaluation tool. Baited cards are qualitative tools that may relate to the number of flying pests. Though captures were recorded and reported, a strict numerical tool that specifies a certain infestation level is not available. Baited cards do not reliably relate to field concentrations of the pest, but do serve as a positive indicator of arrival.

Data in this test are observational rather than strongly quantitative as related to level of infestation. No literature study found has tied card counts to field populations. But a generally recognized action level of one weevil per 400 plants does indicate significance in the planting, and thus importance as an indicator tool for the presence of pepper weevil.

The generally recommended concentration of 10 cards per acre is not practical for this study.  We know that the pepper weevil enters at field edges, and high traffic areas, and that field distribution is clumped.  We placed a card where we anticipated greatest probability of capture, and added scouting as an observational tool. 

Research results and discussion:

Jan-Mar 2013:             Seek cooperation of those off-farm enterprises as well as pepper farmers where monitoring is deemed necessary. Complete. 

Most potential participants willingly engaged in the study.  Two processors preferred non-participation and so traps were located outside the facility.  One farm refused trap placement for fear that the trap would draw weevils to his fields.

April 2013:       Order materials and mount cards in chosen locations. Complete.  

We knew from earlier studies at one processing facility that the weevil is present in our area by May, so the initial traps were placed in mid to late April.  Figure 1 shows an example of the pheromone-baited trap used throughout the study.

May 2013:       Observe and record indications from all cards on a minimum weekly basis. Change pheromone lures in 4-6 week intervals. Complete. 

In April and May cards at or near all five processing/repacking facilities trapped weevils. This outcome was unexpected.  We expected the one facility monitored in 2012 to exhibit weevil presence based on prior year results, and receipt of peppers from Florida and Mexico, but did not expect so general an arrival indication.  This finding put us on alert and we did install sticky cards in other areas. 

June 2013:      Observe and record indications from all cards on a minimum weekly basis.  Complete.

Several farmers requested that they be included in monitoring, and so we accommodated their requests.  In June weevils began to appear at a relatively low level into fields particularly near one processor, and the numbers trapped at all the processors continued upward.  We recommended insecticidal spray initiation to one farmer, who preferred to wait for larger numbers. (The field eventually became infested.) Figure 2 graphically displays the early arrival of pepper weevils to the processing facilities. We included field scouting as a monitoring tool. From prior experience we were alert to the potential for significant populations to develop even though just one weevil had been captured.    Very few weevils had spread to the field by this time.

July 2013:        Change pheromone lures on a 4 to 6 week basis. Change cards as needed. Continue data collection.  Complete. 

Through July and until mid-August, some fields became infested though card counts were low overall.  We continued scouting along with card counts. We recommended initiation of insecticidal spraying to several other farmers as an attempt to control populations of the weevil.  We increased monitoring to surrounding fields and maintained contact with owners on the findings. Figure 3 gives an overview of the sites finally included in the monitoring program. 

Aug-Nov 2013:            Continue card maintenance and monitoring.  Complete.

By mid-August increasing numbers of weevils in the fields were apparent and quickly became widespread.  Two fields which had not been sprayed had heavily infested crops. Scouting, in addition to sticky card counts proved to be a useful indicator of a problem in the field.  The egg laying behavior of the weevil provides a sign of its presence as the egg leaves a small scar on the fruit skin.  After the adult emerges from inside the fruit, it leaves a small hole.  Figures 4 and 5 picture these indicators.  As processors received local peppers their populations of weevil climbed.  Refer again to Figure 3 to see the increase at the processors as the season progressed. By the end of the season the processors were receiving peppers from local farms, which, by that time, had developed field populations.  As fields were disked at season’s end, weevils were epidemic, and the numbers trapped surprising.  In 2012 we trapped approximately 1000 weevils.  In this season, we trapped about 21,000. Cards from the field with the heaviest pest population is shown in Figure 6Figures 7 and 8 graphically display the pattern along with numbers trapped at two more of the fields. This is the typical pattern for all of the areas monitored.   Note the very low numbers of early arrivals and the population growth by season’s end.  Figures 9 and 10 show progression from processor areas to field in two of the areas as the pest “hop-scotches” in its’ spread.

Other – In June we sent a sampling of insects to USDA ARS for confirmation of identity, as we did in 2012.  USDA confirmed the identification as Anthonomous eugenii Cano .

In the last half of the season we set up a small test to compare between lured and non-lured cards to determine if the lures were needed.  The 6 lured cards caught an average of 125 weevils per trap.  The 4 non-lured cards caught 50 weevils per trap.

At both the beginning and end of the season we trapped weevils at the top of a county landfill.

Toward the end of the season, September and October, we stopped at a number of pepper fields that we had never visited to see if there were indications of pepper weevil.  We did this because many farmers are suspicious that we were bringing the weevils to their fields.  In all cases we found pepper weevil, including in the fruits, without ever having been to the fields.  So we are now able to know with certainty that we are not carriers.

Anecdotal evidence indicates that terminal markets, such as the one in Philadelphia, may be another source of importation.  Many farms maintain roadside farm markets and obtain produce from the terminal market to supply their markets, especially for crops that have not yet been harvested from their fields.  In 2013, one such farm which was more or less isolated from other farms had a severe infestation that was apparently started because of the introduction of produce from a terminal market.

Observations

Significant numbers of pepper weevil adults were captured near dumpsters with vegetable refuse, from mid-April to the end of May, at a time when these businesses were importing out-of-state produce.  The local pepper fields only had begun to bear flowers in late May.

Once here, we found that there are many potential ways to spread the adult weevils.  Among the most important is the normal flight dispersal by the adults, but also by the movement of produce bins from infested fields to repackers and the return of these bins to uninfested farms.  One farm in this study was devoid of weevils throughout this season until one day after bins were brought in from a processor.  Weevils were first detected near the packing house, and the next day were found in the field. Vehicular transport may also be important since there are many farm and non-farm vehicles that pass through or are in close proximity to pepper fields.  Licensed waste haulers were observed to transport the vegetable residues in covered dumpsters, but there were numerous occasions where we witnessed other transport in open containers or on flatbeds.  Collection and transport of vegetable waste for animal feed and land application occurs in some localities.  Figures 11 and 12 show two different waste disposal techniques in use.

Tomato and pepper fields are often grown in close proximity to processing facilities and to each other helping the survival and spread of the weevil.  We monitored two tomato fields near to processing facilities and, in fact easily caught weevils, followed by their arrival into nearby pepper fields.  This same pattern happened in 2012.

Discussion 

We have quite a produce handling industry in/near New Jersey – processors, repackers, distributors, auctions, and terminal markets. 

Plenty of food hosts are here for pepper weevil including 3300 acres of peppers, 2900 acres of tomatoes, 900 acres of eggplants and unknown acres of solanaceous weeds

We have not followed the sale of New Jersey peppers to out-of-state buyers.  It is possible that contaminated produce could spread pepper weevil infestations to other pepper production areas including glasshouse production facilities.  We have documented the ability of pepper weevil to survive and reproduce on peppers in a glasshouse situation in New Jersey in late fall/early winter.  In 2012 and 2013 we corresponded with a Dutch researcher who was leading the effort to manage and discover the routes of entry of pepper weevil to the Netherlands, which has a large glasshouse pepper production system.

The management of pepper weevil is further hampered by the fact that established infestations cannot be exterminated.  The currently registered insecticides only suppress populations so that once a field is infested, weekly insecticidal applications must commence or the farmer is likely to have severe yield reduction, especially if the infestation occurs early in the growing season.  Late summer or fall infestations cause little yield loss and farmers who are not aware of pepper weevils may not even notice that their fields are infested.

The amount of annual yield loss probably depends upon the geography of crops; the field rotations of peppers and other solanaceous crops, as well as the number of adult weevils introduced via the processors/repackers/terminal markets; and the detection and timing of initial treatments at the farm level.  Certain farms are more prone to infestations due to their proximity to a weevil source, so that there are many farms that have either had no infestations or minor ones that went unnoticed.  For this reason we must decide whether the weevil problem warrants further investigation and development of recommendations that may influence the economics of processors/repackers/terminal markets, as well as farmers.

In reviewing USDA reports for movement and pricing of pepper varieties into the northeast region, it is apparent that a large, complex marketing network exists involving many different national and international suppliers.  What is remarkable is that pepper weevil has been able to exploit this network enabling it to be repeatedly transported to New Jersey and other pepper growing regions.

We feel that New Jersey is a focal point for this problem as described above.  We have a concentration of processors/repackers/terminal markets that are in close proximity to a significant acreage of peppers and alternate solanaceous host crops.  Undoubtedly, there are other areas in the NE region that have processing facilities, but lack the concentration or the acreage of peppers and other solanaceous crops to create a similar problem there.  No infestations have been reported in New England in recent years (Boucher, University of Connecticut, personal communication) but warrants further scrutiny.   The results from these studies show that the weevil is brought into New Jersey in mid to late spring primarily through the transport of produce from Florida and Mexico.  Similarly, infestations of pepper weevil in Canada and the Netherlands have been the result of transporting infested produce to these areas (Loomans, pers. communication).  In late season here the arrival of two trailers full of peppers from Canada resulted in a large capture of weevils on a sticky card at a processing plant that we were m onitoring.

Conclusions

 What did we learn in 2013

  • Processors/repackers/terminal markets are the most important source of pepper weevil (PW) for New Jersey
  • PW flight dispersal for short distances is important
  • Cannot control PW with pheromone traps
  • Cannot rely on non-lured traps for monitoring
  • From the farm crop protection standpoint, recommendations for insecticidal sprays were followed, except in one instance.  That crop was lost through disease, but the population of pepper weevil was astounding.
  • The adult weevil has proved quite resistant in spite of using different recommended insecticides.  Populations were likely held at bay since a large flush of adults did not occur during the growing season when recommendations were followed.
  • An effective protocol does not appear to exist for their elimination here.

Research conclusions:

We believe that we now know much of the arrival and spread behavior of pepper weevil into southern New Jersey.  The common pattern of infestations over the past several years is elucidated.  We believe that other areas with a similar set of neighboring businesses have or can develop a similar situation. The largest problem in addressing the source is that the pepper weevil is not a regulated pest at this time because it is endemic to Florida and Mexico, and other southern areas, which represent the off season supply of peppers to northern points. The life cycle of the insect, coupled with field distance from the source, impacts its density in the field. A remote field may not suffer economic damage. However, there are other potential sources for insect introduction in addition to those monitored this year i.e. terminal markets and auctions, and even home gardeners.

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary:

Education/outreach description:

Farmers were notified of the location and density of weevils throughout the season via the weekly Rutgers Vegetable Plant and Pest Advisory. 

Two vegetable alerts were issued on May 21 and June 24, 2013. 

A grower alert was sent out on May 31, 2013 by county agricultural agents.

 An overview of results to date was presented at the Mid-Atlantic Vegetable and Small Fruits Workers Conference (November 6, 2013), at a Rutgers University Department of Entomology Seminar (November 8, 2013), and at a Rutgers Vegetable Working Group meeting on November 21, 2013.

 An update of our findings were presented at the NJ Pepper Advisory meeting, January 10, 2014

Results were presented at the Atlantic City Vegetable Growers Conference, February 5, 2014.

 An over-view of the NJ pepper weevil situation was presented at the annual Eastern Branch Meeting of the Entomological Society of America, March 16, 2014.

Project Outcomes

Project outcomes:

We hypothesize that the later-in-season timing of the infestation, and the rapid farmer response, saved the majority of this year's crops from extensive crop loss, but caused a significant material and labor cost to the farmers. One farmer reported a 50% loss and another  a 25% loss. 

Farmers should regard the weevil more as a disease pathogen, rather than an insect pest.  Most insect pests can be controlled with one or two insecticide applications or by modifying production practices, but pepper weevil cannot.  Several farmers who have encountered the weevil for the first time were ignorant of the expense and effort that management of pepper weevil requires.

Farmer Adoption

Farmers have been provided the following guidance for control of pepper weevil:

 Do not plant solanaceous crops within 1 mile of a produce handling facility

 Initiate insecticide program at first bloom using Actara

 Separate peppers from other solanaceous crops as far as possible

 Do not tank mix insecticides specifically for pw control as there seems to be no economic advantage for doing so

 Alternate weekly sprays of neonic insecticide with Vydate

 Steam clean or pressure wash produce bins from outside sources before bringing to farm

 Steam clean/pressure wash any shared equipment with infested farms

 Destroy solanaceous crops immediately after last pick, especially for the early plantings

Assessment of Project Approach and Areas of Further Study:

Areas needing additional study

The current guidance for pepper weevil addresses their presence as a unique, infrequent problem.  However, it is a repetitive and costly problem for which no monitoring and control protocol is given. Assuming that farmers wish to pursue further research on control strategies, we see participants in this process to include industry representatives including processors and repackers, but also representatives from produce auctions and terminal markets.  We need a process predicting potential damage utilizing available tools.

We need a training process for farmers and processors (training in ID via lured cards and scouting).  We need their willingness to institute on farm monitoring (with training provided).  We also desire that processors will monitor their incoming peppers, and take action to address the contamination to their suppliers.

We wish to meet with representatives of the processing/repacking industry to both inform them of the situation and to ascertain what steps may be economically feasible for them to reduce or eliminate the release of pepper weevils from the imported produce.  The New Jersey Processors Association includes at least some of the processors that cooperated with us in monitoring the weevils in 2013.  The association may be able to assist us in arranging meetings with industry representatives towards the management of weevils at their facilities.

We need to work in close association with the Rutgers Cooperative Extension Agents in vegetable production, as well as New Jersey State Department of Agriculture for their input in the transport of agricultural products across state lines and their overview of the health of agriculture in the state.

The participants will be provided with all the research results from the two NE-SARE grants for work done in 2012 and 2013 so that everyone has been apprised of our most recent results.  With this as our starting point our objectives are:

1)     Develop a coordinated plan of action

2)     Develop a list of proposed best management practices to determine what methods of managing weevils are feasible.

3)     Propose field trials for various treatment or handling  of vegetable waste; different methods of sanitizing produce bins; evaluation of effective insecticides; testing of additional alternate controls

4)     Develop region specific field scouting and monitoring procedures

5)     Develop training packages intended for farmers; industry; agri-business fieldmen, extension personnel, and private consultants

6)     Revisef protocols, as needed

7)     Assess our progress at the end of the year

Short term

1)     Develop an effective means of communication alerting area farmers of the presence of weevil

2)     Train farmers in monitoring and identifying pepper weevils on their own if desired

3)     Develop effective means of communicating with processing/repacking/terminal market facilities in detection and monitoring of weevils for evaluating the facilities efforts to reduce pepper weevil survival

4)     Train industry personnel in monitoring and identification of pepper weevils, if desired

5)     Notify shippers, suppliers and recipients of pepper produce of the presence of pepper weevils

Medium term

1)     Industry enact processes or procedures to reduce or eliminate pepper weevils at their facilities

2)     Develop guidelines for industry and farmers for sanitizing produce bins and other equipment handling produce

3)     Evaluate need for regulations or controls

Long term

Develop an overall system of strategies for prevention of future infestations, and/or dealing with infield populations

Acknowledgments 

We would like to thank the cooperating farmers particularly Ed and August Wuillermin, Bob Muth, and George Ruggero.

Addendum

 So far in 2014, we have continued to maintain the pheromone traps at the same facilities as in 2013 and have been recording the number of trapped weevils since April 17.  Our current numbers of weevils caught exceed that which was caught in 2013 in the same time period.  As far as known, as of June 1, only one field has been found to be infested with weevils and it is not certain whether the population is established there.  Three of the five produce handling facilities have been approached about taking measures to help reduce the number of escaped weevils from their respective facilities: one is quite interested to take steps to reduce the numbers of pepper weevils to reduce the impact on local farmers; one is willing to take preventive measures as long as it is economically viable, but thinks that the onus should be on farmers to manage the problem; one recognizes that there may be weevils escaping from their dumpsters but are not interested in taking preventative measures.  The two remaining facilities decline to communicate with us.

 References

 2012 Fruit and Vegetable Crops Statistics & National Rankings. (2013, January 1). . Retrieved June 8, 2014, from http://www.nass.usda.gov/Statistics_by_State/New_Jersey/Publications/Fruit_Vegetables_Rankings/2012Fruit&VegRankingFinal.pdf

Elmore, J., Davis, A., & Campbell, R. The Pepper Weevil. Technical Bulletin, United States Department of Agriculture 1934. Retrieved June 8, 2014, from http://scholar.google.com/scholar?q=elmore+1934&btnG=&hl=en&as_sdt=0%2C3

Ghidiu, G. M., & Rabin, J. (1991). The Pepper Weevil in New Jersey. The New Jersey Grower14(1).

Pest Management Strategic Plan for Bell and Non-Bell Peppers in Delaware, Eastern Shore Maryland, and New Jersey Workshop held February 11, 2008; PMSP (2008, May 7). . Retrieved June 8, 2014, from http://www.ipmcenters.org/pmsp/pdf/DE-MD-NJpepperPMSP.pdf

 

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.