Apopka Weevil  Confirmed in Jefferson County Nursery

Apopka Weevil Confirmed in Jefferson County Nursery

Russ Mizell and Xavior Martini, UF/IFAS Entomologists, NFREC, Quincy

Citrus production in North Florida is expanding rapidly in response to the devastation of citrus in Central and South Florida due to citrus greening disease. Citrus acreage in southern Georgia is also increasing. Florida’s climate is situated in the temperate (North) and subtropical (Central and South Florida) regions. Thus, non-native pests from other similar habitats around the world can and frequently do become established in Florida. For example, some non-native pests of citrus that are well established in subtropical Florida include Diaprepes abbreviatus, better known as the “Apopka weevil,” the sugarcane rootstook borer, and the Sri Lanka weevil, Myllocerus undatus. Both of these weevils feed on citrus leaves as adults and their immature stages feed on the roots. Both species also feed on a wide range of other plant species damaging leaves and roots.

The annual low temperatures observed in North Florida the last few years have been higher, possibly due to climate change, and as a result have enabled some pests usually restricted to the subtropical areas of Florida to expand their ranges into the North Florida temperate zone. In addition, expansion of citrus culture with the corollary acceleration of plant movements across the state increase the risk of pest introduction from southern parts of Florida.

Via this article, we are alerting extension personnel, home gardeners, and more specifically citrus growers and nurserymen that the Apoka weevil, Diaprepes abbreviatus has been detected for the first time in an established population in Jefferson County, FL.  The Apopka weevil  was found in a nursery in Jefferson County, and has not been found in citrus in North Florida to date. The Apopka weevil  has several hundred known host plants including citrus, sugarcane, vegetables, fruits and many woody landscape plants. Sicklepod, Senna obtusifolia, and pokeweed, Phytolacca americana, appear to be favorite adult hosts in North Florida in August-September. The large black and white-striped and often orange colored adults (Fig. 1 – C and 1D) feed on fresh leaves where they place their white egg masses in pouches (Fig. 1 – A)  made from 2 leaves connected together. The larvae (Fig. 1- B) hatch and fall to the ground where they feed on plant roots often at depths of 1-2 feet or more. There are 2 generations per year in southern Florida, but the number and timing of those that will occur in north Florida remains unknown.  Adult weevils are easily detected, and often occur as mating pairs. They are not known to be great fliers; however, the larvae can be found in, and be spread around while infesting plant roots in containers.

Diaprepes abbreviatus more commonly called Apoka Weevil

Fig. 1: Diaprepes abbreviatus (A) eggs (B) larva, (C) orange form adult, and (D) white form adult. Picture by Tai Huang (A) and Lyle Buss (B, C and D).

This weevil is a quarantined pest, so nurseries in infested counties are required to follow specific insecticide treatments prior to shipping outside of the quarantine area.  Producers of any potentially infested crops should monitor visually for the adult weevils by looking for feeding damage and adult weevils on the crop and associated weeds.

Further information on this insect pest can be found in the following UF/IFAS publication:  Diaprepes Root Weevil, Diaprepes abbreviatus.  

Friday Feature:  Flexnet Drip Irrigation System

Friday Feature: Flexnet Drip Irrigation System

This week’s featured video was produced by Netafim to introduce their FlexNet™ drip irrigation system.  Unlike traditional layflat tubing systems that must be pierced for drip-line tubing attachment, their FlextNet plastic tubing has built in connectors to prevent leaks at the hose source. These connectors can be customized to match a farmers specific row spacing from 12-40″.  This innovative irrigation system could be useful for irrigation of vegetables, cucurbits, or other crops with drip irrigation in the row beds.

According to the FlexNet™ website, this system offers the following advantages over traditional layflat systems:

  • Quick Assembly
    Integral welded connectors ensure a secure, leak-proof connection between distribution pipes and laterals (with no teflon or glue required when using Netafim fittings)
  • Agro-Machinery Friendly
    When not pressurized, it’s so durable it can be stepped on or driven over
  • Low Expansion Rate
    Pipe lays flat, has zero axial elongation and will not tangle or bend

FlexNet is simple, flexible and light-weight for maximum portability and quicker movement from field to field. It can be used in surface or subsurface applications and requires no specialized tools for installation.

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If you enjoyed this video, you might want to check out the featured videos from previous weeks:  Friday Features

If you come across an interesting or humorous video, or a new product innovation related to agriculture, please send in a link, so we can share it with our readers. Send video links to:  Doug Mayo

 

Understanding Flush Cycles for Citrus Leafminer Management

Understanding Flush Cycles for Citrus Leafminer Management

Danielle Sprague, Jefferson County Extension and Xavier Martini, UF/IFAS Entomologist, NFREC Quincy

Summer’s in full swing, so citrus groves are actively flushing (growing new leaves). During the flushing period, citrus trees are most susceptible to damage by citrus leafminer, a key insect pest of citrus and related species in the family Rutaceae. The citrus leafminer (CLM) is a small white moth, about 2.4 mm in length. It is more easily detected during the larval stage by the serpentine larval mines (trails of feeding damage) on the underside of new leaves.

Citrus leafminer adult. Photo: James Castner

The larvae of the citrus leafminer (CLM) feed on the new growth or flush of citrus causing serpentine mines to form under the leaf cuticle. The feeding damage results in leaf curling and distortion.  Infestations of CLM on young trees can retard the growth of trees. Another threat concerning CLM in Florida is that the leaf mines provide an opening for citrus canker.  Although citrus canker has not been detected in commercial citrus groves in North Florida, an understanding of CLM biology and interaction with citrus flushing cycles is critical for successful management.

Larvae and leaf mine of citrus leafminer. Photo: Danielle Sprague

Citrus Flush Cycle and CLM

The term “flush” is used in the citrus industry to describe the new foliar growth between bud break and shoot expansion. Citrus trees usually have several flushes per year, depending upon cultivar, climate and crop load. Generally, most citrus cultivars in our area have two major flushes in May and September.

Young citrus trees are most susceptible to damage by CLM, because adults require the new flush for development. Eggs are laid within the flush. After two to ten days, the larvae emerge and feed, causing the mines to occur. Larvae are protected within the leaf and therefore difficult to control. Pupation occurs within the leaf mine and takes anywhere from six to 22 days, depending upon temperature. Adults emerge around dawn and are most active in the morning and evening. In Florida, one generation of CLM is produced about every three weeks, but populations increase when citrus trees are flushing.

Mines from citrus leafminer on young flush. Photo: Danielle Sprague

Monitoring for CLM

Monitoring for adult CLMs can be useful for determining when moths are flying, and aid in making effective management decisions. The most effective means of monitoring CLM is the use of baited pheromone traps containing a female sex pheromone to attract adult males. Another method used for monitoring adult CLM are sticky traps. Sticky traps should be hung on the outside of the canopy and monitored weekly. One to two traps per acre is recommended for monitoring.

Baited pheromone trap for CLM. Photo: Danielle Sprague

CLM Control

Pheromone Mating Disruption

For organic growers, or growers that wish to reduce the use of insecticides to control CLM, a pheromone based mating disruption product called SPLAT-CLM is commercially available. Pheromone disruption consists of releasing a high quantity of the CLM’s sex pheromone to reduce mating between male and female. A reduction in mating results in a reduction of fertilized eggs and resultant damaging larvae.

Biological Control

In Florida, several natural enemies assist with reducing CLM populations. Studies have shown that predation from natural enemies can reduce CLM populations by 90%. Primary predators of CLM include ants, lacewings and spiders. A parasitic wasp, Ageniaspis citricola was introduced into Florida and has become established. The parasitic wasp attacks the immature stages of CLM. Ageniaspis citricola can be requested and obtained for free from the Florida Department of Agriculture and Consumer Services (FDACS). Because it is a specialized parasitoid of the CLM larval stage, it should be released only when mines start to become visible during a flush.

Insecticides and Timing of Application

Nonbearing trees (<4 years old)
For young citrus trees, the most effective means of preventing leafminer damage is the use of soil-drench insecticide applications. Soil-drench applications have limited effect on natural enemies and provide the longest lasting control of CLM. Currently, there are three 4A Mode of Action (MOA) neonicotinoid insecticides (clothianidin, imidacloprid, thiamethoxam) and one group 28 MOA insecticide (cyantraniliprole) labeled for soil applications (Table 1.). It is important to note that all the neonicotinoids share the same MOA, so repeated exposure to the same MOA can result in the development of insecticide resistance.

Soil applications should be made two weeks prior to flushing to allow time for the insecticide to move from the roots into the canopy. To avoid leaching of insecticide away from the root zone, time soil applications to avoid rain events within a 24 hour period.

Foliar applications of insecticides provide a shorter duration of protection from CLM, so timing is critical for optimal control. Foliar sprays directed at CLM should be applied when the flush is about halfway expanded to kill the maximum number of CLM. It is not recommended to spray neonicotinoids, if a soil application has been already made.

Mature Bearing trees
Soil applications of  neonicotinoids are not effective on mature citrus trees, so the only products labeled for use on mature trees are foliar sprays (Table 2.). Achieving leafminer control with foliar applications on mature trees can be difficult due to unsynchronized flushing of trees. Foliar applications should be timed with the appearance of the first visible leaf mines. Be sure to READ THE LABEL and follow all of the label directions.

 

For more information on this topic, use the links to the following publications:

2017-2018 Florida Citrus Production Guide: Citrus Leafminer

UF/IFAS – Citrus Leafminer

2017-2018 Florida Citrus Production Guide

 

 

Water Source Recommendations for Food Safety

Water Source Recommendations for Food Safety

Supplemental water is necessary for good crop yields in fruit and vegetable production. Water quality is equally as important as water quantity when it comes to fruit and vegetable production. Unfortunately, water can transport harmful microorganisms from adjacent lands or other areas of the farm. The water source and how the water is applied influence the risk for crop contamination to occur.

Water is used for various purposes during production: harvesting, and handling fresh produce, irrigation, cooling, frost protection, as a carrier for fertilizers and pesticides, and for washing tools and harvest containers, hand washing, and drinking.

Washing lettuce. Photo Credit: Cornell University Extension

The FDA’s Food Safety Modernization Act (FSMA) proposed water compliance date is not until 2022, but it will be here before you know it. Water quality is an important component of a Food Safety Plan. A good first step in ensuring compliance with FSMA water quality standards is to evaluate the water sources on the farm.  For more information on compliance dates, please visit the Produce Safety Alliance’s Website.

Water Source

The three common sources of water used on farms are surface water, well water, and municipal water.

Surface water includes ponds, lakes, rivers, and streams. It is at the highest risk for contamination because there is limited control on what flows downstream or from adjacent land. Wild and domestic animals, manure piles, and sewage discharges are all potential sources of contamination in surface waters.

The most common water source for North Florida farms is well water. Well water used for farming is at a moderate risk of becoming contaminated, when compared to surface water (highest risk) and municipal water (lowest risk). Wells are at a higher risk of becoming contaminated when located near flood zones, septic tanks, drainage fields, and manure/compost storage areas. The risk of contamination is further heightened if the well was not constructed properly, or if the casing is cracked. Wells should be properly sited, constructed, and maintained to keep contamination risks lower.

a well pump

A recently installed well pump on a North Florida watermelon farm. Photo Credit: Matt Lollar, University of Florida/IFAS Extension

Well Design and Construction

  • Preliminary Investigation – A preliminary investigation helps determine the design of a well. Existing wells in the area should be checked out to help determine depth and potential capacity. If records for the area aren’t available, then test holes should be drilled to determine the best location for water production.
  • Casing – Casing material should be determined based on site characteristics. The casing needs to extend above the surface water level to reduce contamination risks. The casing is sealed in place with grout. A poor grouting job can also promote contamination. Casing diameter is selected based on well capacity.
  • Well Screen – A commercially designed well screen should be installed to minimize hydraulic head loss. Screen diameter and material should be determined based on the preliminary investigation results. Gravel packing is recommended in some areas.

For more recommendations on well design and construction, please visit the University of Florida/IFAS publication: Design and Construction of Screened Wells for Agricultural Irrigation Systems

Please note that it is important to monitor your well water quality at least twice during each growing season.  A list of FSMA approved water testing methods can be found at Cornell University’s Law School Website.

 

Friday Feature:  Satsumas from Farm to Schools

Friday Feature: Satsumas from Farm to Schools

This week’s featured video was produced by Chartwells School Dining Services to highlight their “Farm to School” program.  This video features the relationship that was established with Cherokee Farms, Marianna, Florida to supply every student in the Duval County School District with fresh satsuma citrus.  This story highlights the success of their program for purchasing fresh produce direct from farmers for immediate distribution in school lunches.  For more information on how farmers can participate in this type of marketing program, go to the Florida Department of Agriculture’s Farm to School webpage.

 

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If you enjoyed this video, you might want to check out the featured videos from previous weeks:  Friday Features

If you come across an interesting or humorous video, or a new product innovation related to agriculture, please send in a link, so we can share it with our readers. Send video links to:  Doug Mayo

 

 

Cold Tolerant Citrus Production Workshop – June 2

Cold Tolerant Citrus Production Workshop – June 2

Please join Extension agents and specialists from the University of Florida and University of Georgia for a highly informative Cold Tolerant Citrus Workshop. The event starts at 8:30 Eastern at the UF/IFAS Extension Taylor County office in Perry, Florida.

The following topics will be covered:

  • Backing up your electric powered freeze protection: Mr. Arley Brillion, Mastery Engine Center, St. Petersburg Florida
  • Automating your irrigation, fertigation and freeze protection with air and soil moisture sensors: Doug Crawford, BMP Logic, Trenton Florida
  • Irrigation design for fertigation and chemigation: Dr. Charles Barrett UF/IFAS Suwannee Valley REC
  • Selling citrus – how do I get paid?  Mr. Adam Roe, W.G. Roe and Sons, Winter Haven Florida
  • Latest innovations in freeze protection: Kim Jones, Bethel Oaks Farm, Monticello Florida and Clay Lamar, 1 Dog Ventures, Georgia
  • Tour of Grams Legacy Grove in Perry, Florida: Andy Jackson

The workshop will include lunch and a tradeshow.  Please click HERE to register for the event.  For more information, contact Clay Olson, UF/IFAS Extension Taylor County at 850-838-3508 or Dan Fenneman, UF/IFAS Extension Madison County at 850-973-4138.