According to UF/IFAS, high population densities of Asian Bean Thrips (ABT) continue to appear only in isolated locations.
ABT populations have reached 1.0 per bloom early bloom plantings across multiple farms in southeastern Hendry County. In some cases, populations reached as high as 1.7 per bloom.
Populations reached 8.5 per bloom in plantings within a week of harvest. It’s the highest reported outside of Miami-Dade County.
The late increase in population may affect nearby and/or subsequent plantings.
In northern Collier County, ABT has not yet been reported in plants at the early bloom stage or younger. The pest was found for the first time at up to 0.3 ABT per bloom in older plantings.
In eastern Palm Beach County, populations appear to remain low, at less than 0.1 per bloom.
ABT populations were not reported in southern Glades County and southern Martin County. This indications population density is below sampling threshold.
Photo submitted by Stanley Culpepper/UGA: Shows a blend of yellow and purple nutsedge.
Weed management in vegetable crops across the Southeast remains a diverse and complicated practice that all producers need to be reminded of.
“There are so many components that a vegetable grower has to consider, especially when it comes to weed control. Some production systems you can use tillage. Some you can’t. Some you have plasticulture in a fumigant system. Some that you don’t,” University of Georgia Cooperative Extension weed specialist Stanley Culpepper said.
“Then when you start thinking about herbicides, we’ve been very fortunate over the last 10 years, getting our growers a lot of cool herbicide tools as a component to their management program, but when you’re a vegetable producer and going to have a crop and be in and out in 60, 80, 90 days, you’ve got to think about herbicide carry-over. I can or I can’t use herbicide ‘A’ because of what it could potentially do to the next crop, which means you’ve got to know what the next crop is going to be. You know vegetable guys as good as I do, a lot of times, they just don’t know.”
Producers have to implement the right herbicide and do so at the right rate. They have to use the right irrigation program. The tank also has to be perfectly clean.
“The complexity goes on and on for a vegetable farmer. A lot of decisions have to be made in a 12-month cycle because we could be producing three crops in a lot of our farms,” Culpepper said.
Weed Problems
Certain weed species are also problematic at different times of the year. Weeds that are normally a concern for producers in the spring are not the same as those that are plaguing producers right now. Different weeds require different management strategies.
“Lets start in the spring. In a fumigated plasticulture production system, nutsedge remains the baddest boy that there is. That’s the only weed that can penetrate through the mulch. Nutsedge is still a huge dominant player. In addition to nutsedge, what has really taken its foothold on a lot of my guys has been purslane species and a lot of ours is actually pink purslane; a bunch of different grasses that have always been here and then our amaranth species (not palmer amaranth),” Culpepper said.
“If you look at this time of year, wild raddish is the baddest boy that there is.”
Weed Management
Weed management remains key to successful vegetable production, whether you are talking about now or in the spring. Before plants are ever put in the ground, weed control needs to be a top consideration for producers. Weeds challenge and can overwhelm crops for water, sunlight and nutrients.
Culpepper said in most situations, the weeds are better competitors than the crop.
“Before you ever start a conversation, you say, ‘Look, vegetable weed control is really challenging. There can’t be any weed emerge at planting.’ It’s very likely that if we’re going to implement a herbicide program we’ve got to start it before we ever plant,” Culpepper said.
“In transplanted onion production, obviously, very important to Georgia, we have an excellent herbicide program that will be successful probably 95-plus% of the time, which is really, really good. If you wanted to grow seeded onion production in the state of Georgia, I don’t think you’ll have a chance because you can’t manage the weeds. Or if you do, you’ll spend a tremendous amount of money.
“There’s the same crop per se grown two different ways; one is very unlikely to be successful and the other is very likely to be successful with regards to weed management.”
“If you wanted to seed cabbage, because of wild raddish, you’re in trouble. But if you want to transplant cabbage, I have a herbicide you can put out before you transplant, and I’ll take the wild raddish out.
“There’s two examples, exact same crop, of how you want to process or implement your program will determine how successful you’ll be.”
A cold and rainy winter has been challenging so far for Alabama vegetable producers. Joe Kemble, Alabama Extension vegetable specialist, cautions growers that though it may be chillier, that does not eliminate certain diseases that can be problematic.
“I will say on the vegetable side, things are a bit slow. Weather’s been not exactly ideal. The rainfall we’ve been having, I would be concerned about things like Anthracnose, leaf blights; things that cause leaf blights on greens,” Kemble said. “I’d say be diligent and keep an eye out because the weather, unfortunately, yeah it’s cold but the afternoons warming up and still in these 45, 50, 60-degree days, that is warm enough for some of these diseases to keep moving around.
“The cold weather does not eliminate that problem, unfortunately.”
Yellowmargined Leaf Beetle
Farmers also need to be wary of potential insect problems even during cold weather conditions, specifically with the yellowmargined leaf beetle. Unlike some insects that prefer summer, or warm conditions, the yellowmargined leaf beetle likes cooler weather and will impact brassica crops.
“It’s fairly new to our area the last few years. They’re incredibly hard to kill. If you’re growing cabbage, they can hide very well in the heads,” Kemble said.
“It’s really hard to get sprays sometimes on them. You’d be harvesting and start finding all of these holes in leaves and things. Unfortunately, the yellow margined leaf beetle is pretty good at what it does in terms of holes and things like that.”
Stormy Sparks’ message regarding whitefly management remains the same: If you’re done with the crop, get rid of that crop.
Sanitation remains the best defense against whitefly buildup in Southeast vegetable and cotton crops. Even watermelon producers, who don’t have to contend with whiteflies as much as cantaloupe and cucumber farmers, are encouraged to do their part in preventing potential infestations in other fields.
“Watermelons present a unique challenge because we’re dealing with so many more growers,” said Sparks, a University of Georgia Cooperative Extension vegetable specialist.
“If you look at it from strictly a financial standpoint this season, in many cases there’s no emphasis on whitefly management in watermelons. But if we don’t get rid of the crop, we can distribute them on watermelons and then they can build up in those crops that are left standing and move into cotton. That’s basically what happens.”
Sanitation is a key management strategy all farmers can implement when managing whiteflies. Once farmers are done harvesting their spring vegetables, they need to get rid of them.
Watermelons Left in the Field
But in many watermelon fields, watermelons are sometimes left in the field long after the final harvest. This can be largely attributed to “pinhookers” or people who buy the remaining watermelons in a field with the purpose of reselling them. However, this leaves a watermelon field susceptible to whitefly infestations since so much of the crop is left in a field for weeks, if not months.
“You can find fields in the fall that were planted in the spring,” Sparks said.
Whitefly Impact
Whiteflies migrate from winter vegetables to spring vegetables to agronomic crops, like cotton, to fall vegetables and back to winter vegetables. Whiteflies cause feeding injury issues in vegetables and transmit two viruses: cucurbit leaf crumple virus and cucurbit yellow stunting disorder virus.
Weed management remains a vital strategy all vegetable producers need to implement in order to have a successful season.
University of Georgia Cooperative Extension weed scientist Stanley Culpepper implores farmers to stay vigilant in keeping weeds out of their fields.
“What you want to do is you want to remove weeds from the field because they compete with the crop. They compete for water. They compete for sunlight. They compete for your nutrients,” Culpepper said. “In most situations when you talk about a vegetable crop, not all, in most situations the weed is a better competitor than the crop. If you’re in corn, corn’s a really good competitor. A lot of weeds can’t compete with corn.
“But in most of our produce crops, because we start off very small and it takes a long time to get going, those weeds will basically take advantage of the lower competitiveness of the crop and then win out.”
Weeds are problematic no matter what time of the year and no matter what crop is being produced. Whether you are talking about wild radish or primrose this time of year or nutsedge in a fumigated plasticulture production system during the spring, weeds are a top priority that need to be considered before planting ever begins.
“Before you ever start a conversation, you say look vegetable weed control is really challenging. There can’t be any weed emerge at planting. It’s very likely that if we’re going to implement a herbicide program we’ve got to start it before we ever plant,” Culpepper said.
“It’s not like cotton. It’s not like corn. It’s not like soybeans where okay I made a little mistake, I’ll catch up. That does not exist in the world of weed control in southeastern vegetable production.”
WASHINGTON — The U.S. Department of Agriculture (USDA) is allocating more than $70 million to support 383 projects under the Plant Protection Act’s Section 7721 program to strengthen the nation’s infrastructure for pest detection and surveillance, identification, threat mitigation, to safeguard the nursery production system and to respond to plant pest emergencies. Universities, states, federal agencies, nongovernmental organizations, nonprofits, and Tribal organizations will carry out selected projects in 49 states, the District of Columbia, Guam, and Puerto Rico.
“State governments, academic institutions, and other essential cooperators across the country use these USDA funds to protect American crops and natural resources and ensure the marketability of our agricultural products across the globe,” said Greg Ibach, Under Secretary for USDA’s Marketing and Regulatory Programs.
The fiscal year 2021 project list includes 29 projects funded through the National Clean Plant Network (NCPN). The NCPN helps our country maintain the infrastructure necessary to ensure that pathogen-free, disease-free and pest-free certified planting materials for fruit trees, grapes, berries, citrus, hops, sweet potatoes, and roses are available to U.S. specialty crop producers.
Since 2009, USDA has supported more than 4,400 projects and provided nearly $670 million in funding through the Plant Pest and Disease Management and Disaster Prevention Program. Collectively, these projects allow USDA and its partners to quickly detect and rapidly respond to invasive plant pests and diseases.
In FY 2021, funded projects include, among others:
Asian giant hornet research and eradication efforts: $944,116 in Washington and other states;
Exotic fruit fly survey and detection: $5,575,000 in Florida and California;
Agriculture detector dog teams: $4,287,097 to programs in California, Florida, and nationally to support detector dog teams;
Honey bee and pollinator health: $1,337,819 to protect honey bees, bumble bees and other important pollinators from harmful pests;
Biosecurity: $1,339,183 to Texas to monitor for pests in agricultural shipments at ports of entry;
Stone fruit and orchard commodities: $1,158,000 to support pest detection surveys in 10 states including New York and Pennsylvania;
Forest pests: $876,485 for various detection tools, control methods development, or outreach to protect forests from harmful pests in 16 states, including Arkansas, Indiana, South Carolina, and New Hampshire;
Phytophthora ramorum (sudden oak death pathogen) and related species: $513,497 in 14 states and nationally for survey, diagnostics, mitigation, probability modeling, genetic analysis, and outreach;
Solanaceous plants (including the tomato commodity): $434,000 to support surveys in 13 states including Texas, Mississippi, and South Carolina.
USDA will use $14 million to rapidly respond to invasive pest emergencies should a pest of high economic consequence be found in the United States. In the past, USDA has used these funds to rapidly respond to pests such as grasshoppers, Mormon crickets, the Asian giant hornet, coconut rhinoceros beetle, exotic fruit flies, and the spotted lanternfly.
As the United States and the world recognize the International Year of Plant Health through June 2021, this funding highlights USDA’s continued commitment to safeguarding our agricultural resources for current and future generations.
Learn more about the Plant Protection Act, Section 7721 on the USDA Animal and Plant Health Inspection Service (APHIS) website: www.aphis.usda.gov/ppa-projects.
Chilli thrips, Scirtothrips dorsalis, was first detected in southern highbush blueberries in Florida in Orange, Sumter and Hernando counties during the summer of 2008. It is a major pest of many host plants, including vegetable, ornamental and fruit crops.
Figure 2. Deformed leaves are the result of chilli thrips feeding.
FEEDING DAMAGE
In blueberry, chilli thrips feed on young leaves, causing leaf bronzing (Figure 1) and shoot dieback in late spring to early summer shortly after the bushes are pruned. Some infestation symptoms include the edges around younger leaves and stems are eaten, and bushes become pale green with deformed leaves (Figure 2). During a heavy infestation, blueberry cupped leaves are quite noticeable, with larger leaves curving inward (Figure 3).
Overall, chilli thrips affect plant vigor and reduce the number of berries the following season.
IDENTIFICATION AND LIFE STAGES
Figure 3. Blueberry cupped leaves are a symptom of chilli thrips infestation.
Chilli thrips are smaller than flower thrips and are approximately 0.04 of an inch long. They have dark fringed wings and dark spots across the back of the abdomen (Figure 4).
Chilli thrips have four life stages: egg, larva, pupa and adult, including two actively feeding larval instars and two non-feeding pupal instars. Female thripsinsert their eggs into blueberry tissues, and the eggs hatch in about six to eight days. Females are capable of laying between 60 to 200 eggs.
Newly hatched larvae pass through two larval stages (first instar and second instar). These larval instars last for about six to eight days, during which time they feed on blueberry tissues. They then pass through a prepupal and a pupal stage, during which time they do not feed. Chilli thrips complete their life cycle in 17 to 21 days under ideal conditions.
In Florida, most of the chilli thrips outbreaks in blueberries were recorded from late May to September on new growth.
Figure 4. Adult chilli thrips have fringed wings.
Photo by Lyle J. Buss, University of Florida
MANAGEMENT METHODS
Chemical insecticides including the use of Delegate® (spinetoram), Apta® (tolfenpyrad), Rimon® (novaluron), Assail® (acetamiprid) and Sivanto® (flupyradifurone) are the primary means to manage chilli thrips populations in blueberries.
Delegate® is effective in controlling larvae and adult chilli thrips. Apta® inhibits feeding of larval and adult thrips. Rimon® affects egg and larval development due to its growth regulator characteristics. Assail® is a neonicotinoid insecticide that can control larvae and adults due to systemic qualities. Sivanto® also controls larval and adult thrips and behaves similarly to neonicotinoids.
In organic production, Entrust® (spinosad) is the primary insecticide tactic. However, Azera® (pyrethrins + azadirachtin) and PyGanic (pyrethrins) can also be used in organic production.
Management for chilli thrips includes eliminating host plants, including weeds, that support their growth and development. Beneficial insect predators such as Geocoris spp. and Oriusinsidiosus feed on thrips and need to be considered when using chemical pesticides.
Around SW Florida, whiteflies continue to bounce up and down, as heavy rains and cool nights slowed them down a few days in most places. Population numbers and nymphs are building in a number of mature fields. Growers should increase monitoring efforts as pressure is likely to increase over the next few weeks while older fall fields are terminated. Growers are reporting some problems such as sooty mold in older fields with high whitefly numbers.
In the Manatee Ruskin area, respondents indicate that whitefly numbers have declined in the face of colder weather, and pressure is mostly light.
On the East Coast, reports indicate that whiteflies are reaching high numbers in some older eggplant. Growers and scouts report persistent pressure in tomato with growers spraying as needed.
Reports from Homestead indicate that whiteflies are increasing in a number of crops and that tomato yellow leaf curl virus is widespread in tomato.
Here is the weekly scouting report of the Asian Bean Thrip (ABT) in various counties in Florida.
According to UF/IFAS, outside of Miami-Dade County, high population densities of ABT continue to be in isolated occurrences only.
Photo graphic by UF/IFAS.
The highest instances of ABT continues to be in eastern Palm Beach County. Populations are as high as 4.0 per bloom. However, it has not been reported in western Palm Beach County.
In southeastern Hendry County, population density averaged between 0.1 and 1.6 ABT per bloom. In northeastern Hendry County, populations are reported from 0.1 to 0.6 ABT per bloom. In western Hendry County, ABT population density was reported at 0.2 ABT per bloom. In central Hendry County, ABT was identified only in a single flower.
For the first time, ABT was reported in southern Glades County at 0.1 ABT per bloom.
In northern Collier County, ABT was not identified this week. This suggest population density is near sampling threshold. In southern Martin County, ABT was not identified this week, with a previous report of only one ABT identified in a single flower.
Isolated incidences of higher populations have been discovered at various sites after harvest in an adjacent field.
Ayanava Majumdar, Extension Professor in Entomology and Plant Pathology at Auburn University, cautions all vegetable producers one insect to be wary of right now is the yellowmargined leaf beetle.
Unlike some insects that thrive only during the summer, or warm conditions, the yellowmargined leaf beetle likes cooler weather and will impact brassica crops.
“It’s a small beetle that when you scout for it, it may drop off the plant. Farmers may miss it and think it’s a caterpillar but it’s actually this leaf beetle that likes the cool weather,” Majumdar said.
“It does a massive amount of damage, not only this time of year, but the population just gets worse in spring. Farmers who already have yellowmargined leaf beetles will probably get worse in spring. We need a timely intervention, chemically or organically speaking, to stop the yellow margined leaf beetle.”
Identification Important
Majumdar said the first step in yellowmargined leaf beetle management is to make sure farmers identify it correctly.
“The beetle and the larva, they feed together on the leaves. They especially love turnips, turnips and napa cabbage. They will tear up the turnips and cabbage at first before moving on to other brassicas,” Majumdar said. “The one thing to remember is BT products … they don’t work against the beetle. It will take care of the caterpillars but not the beetles. Diagnosis is very important before farmers take off with control.”
Another concern that producers need to be mindful is insecticide resistance. Majumdar stresses that growers not overspray, because it could lead to resistance issues.
