Hendry County Extension PO
Box 68 LaBelle, Florida 33975-0068 Phone (863) 674-4092
SOUTH
FLORIDA
VEGETABLE
PEST AND DISEASE
HOTLINE
Insects
Whiteflies
Reports
indicate that whitefly numbers in the Manatee Ruskin area are ramping up
rapidly along with TYLCV in a number of fields.
Around
Southwest Florida, growers and scouts report that whiteflies remain high in
many locations but respondents indicate numbers seem to be declining in some
places.
Reports indicate
that TYLCV is moving in places especially where growers are not using TYLCV
resistant cultivars, and cucurbit leaf crumple virus has become widespread in
watermelons and cucurbit yellow stunting disorder virus is also becoming
common in watermelon as well. Some vine
decline (squash vein yellowing virus) is also being reported in watermelon. Some tomato fields in SW Florida are
also experiencing a high percentage of irregular ripening.
Respondents in
Miami Dade County indicate that whitefly remains common on tomato, eggplant, squash
and other host crops. TYLCV is common
in many tomato fields and has reached nearly 100% infection levels in a few.
Cucurbit crops
at various locations around Miami-Dade are also showing high incidence of
silverleaf stemming from heavy whitefly infestation.
In the Palm
Beach area, whiteflies are increasing in tomato, squash and eggplant, and have
become a problem especially in Palm Beach County. Whiteflies are reportedly building up in
leafy brassicas in the Glades.
As noted above
this spring is shaping up to be a bad season for whitefly and attendant
problems including virus in tomatoes and melons, silverleaf in squash and
irregular ripening in tomato.
Irregular
ripening is a physiological disorder unrelated to virus but caused by feeding
of whitefly nymphs, not adults. The
threshold for irregular ripening is 1 nymph per 2 leaflets. Nymphs are best monitored on the underside of
the lower (5-7th node) leaves.
The whitefly
situation has been exacerbated by a warm mild dry winter and the fact that many
tomato fields around South Florida have been abandoned after one pick due to
low prices. In addition, due to low
prices growers have been reluctant to spray. Even
though most of the abandoned acreage has been sprayed with an herbicide, in
many cases, there is still plenty of green living tissue to support whiteflies
as well as other pests and diseases.
Some fields, I have visited literally have clouds of whiteflies
streaming out of them and settling on nearby spring plantings. This situation is
not playing out well for spring crops.
Field hygiene
including rapid and timely crop destruction and clean up should be a high
priority and should be an integral part of the overall strategy for managing
whitefly populations, TYLCV incidence, and insecticide resistance. These practices
will help reduce the onset of the initial infestation of whitefly, regardless
of biotype, and lower the initial infestation level during the cropping period.
Disrupt the
virus-whitefly cycle in winter by creating as long a break in time and/or space
as possible between fall and spring crops, especially tomato, cucurbits and
other crops where whitefly vectored viruses are an issue.
Promptly and
efficiently destroy all vegetable crops within 5 days of final harvest to
decrease whitefly numbers and sources of plant viruses like TYLCV.
Destroy old
crops quickly and thoroughly after harvest, killing whiteflies and prevent
re-growth.
Spray
first with a tank mix of pyrethroid and malathion to kill whiteflies in the old
crop. Use a contact desiccant (“burn
down”) herbicide in conjunction with a heavy application of oil (not less than
3 % emulsion) and a non-ionic adjuvant to destroy crop plants and to kill
whiteflies quickly.
Time burn down
sprays to avoid crop destruction during windy periods, especially when
prevailing winds are blowing whiteflies toward adjacent plantings.
Treat spring
plantings of tomato with a systemic insecticide in the transplant water. (Table 1). If
on drip, make a second soil application in 30 days using a systemic insecticide
of different mode of action
Scout
crops every week and apply insecticides as needed to maintain control. Target nymphs once the threat of immigration
from old crops has passed (Table 2).
Table
1; Systemic insecticides applied to soil for whitefly control
|
Common name
|
Mode of Action
|
Trade Names
|
Rates
|
|
Imidacloprid
|
4A
|
Various
|
Check Label
|
|
Thiamethoxam
|
4A
|
Platinum 75 SG
|
1.66 - 3.67
|
|
|
4A
|
Venom 70%
Scorpion 35 SL
Certador 10%
|
5 - 7.5 oz/ac
9 -1 0.5 fl oz/ac
32.5 - 47.5 fl oz/ac
|
|
Flurpyradifuron
|
4D
|
Sivanto 200 SL
|
21-28 fl oz/ac
|
|
Verimark
|
28
|
Verimark 18.7%
|
5-10 fl oz/ac
|
|
Efficacy Ratings for Insecticides and Miticides on Tomato
|
||||||
|
|
|
Whiteflies
|
Other pests controlled
|
|||
|
MOA
|
Active Ingredient
|
Whiteflies
|
Southern Armyworm
|
Spider mites
|
Stinkbugs
|
Leafminer
|
|
4A
|
dinotefuran
|
E**
|
|
|
G
|
|
|
4A
|
imidacloprid
|
E**
|
|
|
|
|
|
4A
|
thiamethoxam
|
E**
|
|
|
G
|
|
|
4D
|
flupyradifurone
|
E**
|
|
|
|
|
|
23
|
spiromesifen
|
E†
|
|
E
|
|
|
|
23
|
spirotetramat
|
E†
|
|
G
|
|
|
|
7C
|
pyriproxyfen
|
E†
|
|
|
|
|
|
28
|
cyantraniliprole
|
E**
|
E
|
|
|
E
|
|
1B
|
malathion
|
G*
|
|
|
|
|
|
3A
|
beta-cyfluthrin
|
G*
|
F
|
|
G
|
|
|
3A
|
bifenthrin
|
G*
|
|
|
G
|
|
|
3A
|
esfenvalerate
|
G*
|
G
|
|
|
|
|
3A
|
fenpropathrin
|
G*
|
F
|
|
F
|
|
|
3A
|
lambda cyhalothrin
|
G*
|
F
|
|
|
|
|
3A
|
permethrin
|
G*
|
G
|
|
|
|
|
3A
|
zeta-cypermethrin
|
G*
|
G
|
|
F
|
|
|
4A
|
acetamiprid
|
G
|
|
|
|
|
|
9
|
pymetrozine
|
G†
|
|
|
|
|
|
16
|
buprofezin
|
G†
|
|
|
|
|
|
21 A
|
fenpyroxiamate
|
G
|
|
G
|
|
|
|
4A
|
clothianidin
|
F**
|
|
|
|
|
|
Unk.
|
horticultural mineral oil
|
F†
|
|
G
|
|
|
|
Unk.
|
Azadiractin
|
F†
|
|
|
|
|
|
Unk.
|
Soap, insecticidal
|
F†
|
|
|
|
|
|
* OP+Pyrethroids tank mix.
** Most Effective
as a drench.
† Effective primarily against nymphs
Check labels before using any pesticide.
|
||||||
For more whitefly management tips – see:
Recommendations for Management of
Whiteflies, Whitefly-Transmitted Viruses, and Insecticide Resistance for
Production of Cucurbit Crops in Florida - http://edis.ifas.ufl.edu/in871
Management of Whiteflies, Whitefly-Vectored
Plant Virus, and Insecticide Resistance for Vegetable Production in Southern
Florida - http://edis.ifas.ufl.edu/in695
Worms
Around Southwest Florida, worm pressure is low
to moderate but starting to pick up.
Respondents have noted some problems with loopers in tomato and a mixed
bag of beet armyworms, southern armyworms and loopers are causing rind damage
in some watermelons. A few diamondback moths are showing up in crucifers.
On the East Coast, worm pressure remains
mostly low. A few European pepper
moth larvae have been reported in bell pepper. Respondents indicate that
diamondback moths are causing some problems in leafy brassicas and some growers
have reported difficulty in trying to get them under control.
European pepper moth has been in Florida
since at least 2011 and may be increasing in numbers. The adults have a
wingspan of 0.75 to 0.83 inch. The
forewings are gray-brown in color with two yellowish-white transverse lines.
The outermost of these lines has a pronounced "finger" that points
towards the back edge of the wing. When at rest, the wings are held out from
the body forming a triangle. The adult body measures 0.35 to 0.5 inch in
length. The head, antennae and body are olive brown. The abdomen has
cream-colored rings encircling it. The legs are pale brown.
Upon hatching, the larvae have a shiny dark
head and a salmon pink body with a line of separated brown to gray spots
extending across and around each segment. On some segments, there are two
transverse rows of these spots. If you look at these spots with a hand lens,
you will see at least one short, stout hair emerging from each of them. There
is also a hard-dorsal plate (or sclerotized region) located on the segment just
behind the head. This plate is the same color as the head capsule.
As the larvae grow, their background color
changes to a creamy white or light brown or dirty white color. The color
can vary depending on the host plant. In some cases, the background color of
the larvae can even be quite dark (due to recent feeding activity) making the
spots hard to see. Prior to pupation, they can reach 0.7 to 1.25-inch-long and
become pearly in appearance. They also seem to lose their spots just before
pupation.
The European pepper moth feeds on a wide
range of vegetable crop and weedy hosts and can damage to roots, leaves,
flowers, buds and fruit on which it feeds as larvae. It will often bore into fruit while feeding.
For
more information and photos – see http://entnemdept.ufl.edu/creatures/veg/leps/european_pepper_moth.htm
Reports from the Ruskin area indicate that
worm pressure from a mixed bag of species remains steady and respondents note
that pinworm has emerged as the #1 lep problem in many tomato fields. One scout remarked that they have not
seen this level of pinworm activity in nearly 25 years. Diamondback moths
remain active in crucifers and have reached high numbers in some fields.
Around Homestead, army worms are active in
a variety of crops.
Respondents in the Glades indicate that armyworms
are spotty in corn as the crop moves away from the Lake and pressure low to
very low in most places. Southern
armyworms are reportedly causing some issues in other vegetables on the muck.
Pepper Weevil
Pepper weevils are established in many
pepper fields around Southwest Florida and numbers are building as the season
progresses. Some growers report
having abandoned fields where weevils have gotten out of control.
Reports from East Coast production areas
indicate that pepper weevil numbers are high to extremely high in all counties
and will curtail extended production in some older pepper fields. Scouts report signs of finding foliar
feeding in eggplant in some places. Young pepper planted near older fields are
at the highest risk.
Pepper weevils are becoming common in the
Homestead area.
Scouting is importance as with other pests
to detect infestations at an early stage. In the absence of Vydate, growers
may want to look at Exirel, Actara, Rimon, Dimilin and the pyrethroids to knock
down adults. Growers should be aware that you cannot spray your way out of this
problem but need to take a pro-active IPM approach throughout the season
including good sanitation and destruction of old fields and separation of
planting in time and space with a crop-free period between fall and spring
plantings where practicable.
Thrips
Growers and scouts report a significant
increase in thrips pressure in most areas.
On the East Coast, respondents indicate
thrips are increasing and affecting pepper quality in most areas in Palm Beach
County where control has been elusive. They are less of a problem in Martin County
but scouts note that populations are increasing in many places and in St Lucie
county where control measures have been more effective. Scouts report they are
mostly western flower thrips with a sprinkling of Thrips palmi.
Some
growers have reports swarms of migrating thrips around Pahokee which are
readily attracted to bright clothing like a yellow shirt. These thrips are moving into bean fields and
may be a cause for concern.
Around Homestead, common blossom thrips and
western flower thrips, vector of TCSV and other tospoviruses continue to be a
threat. Growers should scout fields
carefully to detect their presence in tomato as well as weedy hosts near the
fields and in the surrounding area.
Tomato chlorotic spot virus is widely present in many tomato
fields. Reflective plastic mulch may be
useful to repel thrips early in the cropping cycle.
Melon thrips are also causing problems
around Miami Dade County. Reports
indicate numbers are high in eggplants and adults are being found in squash, cucumber,
beans and okra as well.
Thrips have been mostly low in South
Florida but scouts continue to report finding a few thrips vectored groundnut
ringspot virus and tomato chlorotic spot virus infected plants here and there.
Around Southwest Florida, Thrips palmi are also becoming serious
problems in several pepper fields, as well as some eggplants and they are also
starting to bronze some leaves in some watermelon fields. Growers report that where present they
have presented a challenge to control.
Around Hillsborough County, thrips numbers are
on the rise.
Growers and scouts should learn to identify
thrips species and take a soft IPM approach to reduce numbers and favor
beneficial insects such as minute pirate bug which have been shown to help control
populations.
Radiant, Movento, Torac, Exirel and Requiem
in rotation can be used to manage thrips.
Addition of non-ionic surfactant in tank mix to will increase
effectiveness on insecticides.
Aphids
Around the East Coast, aphids have become common
in a variety of crops with flights of winged and nymphs building on foliage in
many places.
Growers and scouts in Southwest Florida,
report that aphids are patchy and have required control in several places.
In the EAA, aphids are still an issue in
sweet corn resulting in honey dew and sooty mold on the ears as the corn nears
maturity. They are present in low
numbers throughout the growing cycle, but tend to flare up at the end. The numbers on the flags and silks are low
while most the colonies (which remain small) are located on the underside of
leaves up and down the plant. Aphids are
also showing up in leafy greens and brassicas. as well.
Lesser cornstalk borer
Around the Glades, lesser cornstalk borer
trap counts remain fairly high on the sand lands around Clewiston. Depending on location numbers are up and
down based on moisture levels in the field.
Counts on muck soils are declining with lower populations.
Spider mites
With dry conditions, spider mites are flaring
up in a number of locations around South Florida on cucurbits, eggplant and
tomatoes.
Broad Mites
Around Southwest Florida, broad mites
remain widely present and persistent in pepper and eggplant.
Growers and scouts on the East Coast report
a downward trend in broad mite pressure apart from some hotspots where they
remain a problem.
Silkfly
In the EAA, silk fly maggots are showing up
in ears as they near harvest while adults remain low with the highest numbers
being around the lake. Levels of
both adults and immatures can be characterized as low.
Around Homestead, corn silk flies continue
to cause problems.
Growers should scout corn fields carefully
for silk fly infestation. Certis
Bait pellets have shown significant reduction of adults and silkfly damage on
corn ears. Pyrethroids can also be used
to reduce silk fly adults.
Stinkbugs
Growers and scouts are finding stinkbugs
and leaffooted bugs especially in older plantings and some growers have had to
apply pyrethroids. Several scouts
have noted an increase in stinkbugs especially where more selective insecticide
are being applied.
Leafminer
Leafminers appear to be declining in most
locations although they are still around and causing some problems in places.
Diseases
Late Blight
Late blight has slowed down in most places
around Southwest Florida now largely under control on most farms except for a
few places where scouts have noted some new infections.
Target Spot
Around Immokalee, target spot continues to
remain an issue especially in fields nearing harvest or being harvested.
Respondents on the East Coast target spot is
mostly low.
Target spot remains active in Homestead.
Bacterial Spot
Around Southwest Florida, bacterial spot is
present at low levels but is still creeping around is some pepper and tomato fields.
On the East Coast, bacterial spot is increasing
in non- resistant pepper and in tomato.
Bacterial leaf spot is remains active in a
number in tomato fields around Homestead.
Early Blight
Alternaria is increasing on tomato around south
Florida. Some of this is associated
with leafminer damage.
Low levels of early blight have also been
reported around Manatee County.
Early blight has hit some potato plantings
hard where it has moved in on wind damaged foliage assisted by foggy morning. In the worst-case scenarios, yields will
suffer.
Powdery Mildew
Growers and scouts report powdery mildew is
starting to increase in some watermelons and also moving in squash around
Southwest Florida.
Powdery mildew is present in cucumber and
squash around Palm Beach County and is also starting to show up on some
Cubanelle pepper as well.
Growers and scouts indicate that powdery
mildew is widespread in cucurbits around Homestead including squash and bitter
melon.
Dill producers are reporting some issues
with powdery mildew on dill.
Growers are getting good control with
products like Fontelis, Quintec, Torino, and Rally.
Downy Mildew
On the East Coast, downy mildew has jumped
on mature squash in recent days.
Around Immokalee, downy mildew is active in
cucumbers and starting up in some watermelons and in cantaloupe.
Downy mildew is also present on squash in
Homestead.
In the EAA and elsewhere, downy mildew is
causing some issues in cole crops including cabbage, kale and radish.
In the Glades, downy mildew on lettuce remains
persistent, generally at low levels due to good management.
Downy mildew continues to plague basil
producers and is increasing with cooler humid nights and foggy conditions.
Phytophthora
Reports from Palm Beach County indicate
Phytophthora is causing problems in some older pepper in areas where it is
traditional a problem. It is also
hitting some eggplant where fruit are becoming infected on the ground as well
as some double crop squash.
Phytophthora is causing some problems
around Homestead.
Tomato Chlorotic Spot Virus
Tomato chlorotic spot virus (TCSV) is
mostly low and stable but can be found in all counties in South Florida. Incidence remains higher in Miami Dade
County where TCSV can be seen in almost every field but respondents indicate it
is not as bad as in previous years.
Early symptoms of infection are difficult
to diagnose. In young infected
plants the characteristic symptoms consist of inward cupping of leaves and
leaves that develop a bronze cast followed by dark necrotic spots.
Tomato chlorotic spot virus causes necrosis
in tomato leaves and stems, and causes ringspots and other deformations of the
fruit. The symptoms are nearly
identical to those of groundnut ringspot virus and laboratory diagnosis is
necessary to distinguish on from the other.
The use of virus-free transplants, insecticides
to control thrips, rouging infected plants, SAR elicitors such as Actigard, and
UV-reflective mulch will likely be effective managing TCSV.
Tomato Yellow Leaf Curl
A few scattered TYLCV infected plants have
been reported in tomatoes in all production areas around South Florida.
On the East Coast TYLC is increasing in
some older tomato.
TYLCV is common around Homestead and
infection rates are approaching 100% in some isolated fields.
TYLCV is increasing quickly in many fields around
SW Florida and has reached infection rates have surpassed 50% or more in some
older fields and is showing up more frequently in younger fields.
With the huge number of whitefly moving off
abandoned fields, lack of cold weather and very high whitefly counts being
reported in many fields, the situation is ripe for virus to explode in the
spring crop. Growers would be
advised to rapidly and efficiently destroy abandoned fields and aggressively
target whiteflies in younger plantings.
Rouging infected plants in younger fields
is advised.
Watermelon mosaic virus
Growers in few locations around Southwest
Florida are experiencing problems with mosaic in melons and squash.
Growers and scouts in Homestead report
mosaic virus is common in squash.
Cucurbit leaf crumple virus
Around Homestead, cucurbit leaf crumple
virus is widely present in squash.
In Southwest Florida, cucurbit crumple leaf
virus is widely present and increasing in watermelons.
Cucurbit yellow stunting disorder virus
Cucurbit yellow stunting disorder virus is
now becoming more common in watermelons around South Florida.
Vine Decline
Scouts report that squash vein yellowing
virus (SqVYV) (aka vine decline) is present in several watermelon fields around
Southwest Florida.
Cucurbit Virus Advisory
Cucurbit crumple leaf virus (CuLCrV) along
with squash vein yellowing virus (SqVYV) (aka vine decline) and Cucurbit yellow
stunting disorder virus (CYSDV) are all whitefly transmitted viruses which have
appeared relatively recently in Florida. Scouts are already finding all
three viruses in watermelon around SW Florida.
The fact that watermelon growers around SW
Florida saw major issues with CYSDV last spring and a re-emergence of vine
decline (SqVYV) after several relatively quiet years, coupled with the fact
that CuLCrV is widely present at low levels in squash and water melons this
past fall suggests growers should be alert this spring and practice aggressive
scouting and whitefly management in these crops.
We have had another relatively mild winter
to date without any cold weather to take out the wild cucurbit hosts (balsam
apple, bur cucumber etc.) of these viruses so there is high probability that
these viruses could over winter and be ready to jump into spring plantings.
In addition, we are seeing very high
whitefly numbers around SW Florida. Even though these are primarily moving out
of tomato (a non-host), they are hunger and could acquire one or more of these
viruses while moving around before settling down in a squash or melon
field.
As you may know Georgia watermelon
producers experienced major issues with cucurbit crumple leaf virus this fall. Crumple leaf also infects beans and caused
major issues in beans as well.
In short, the stage is being for these
whitefly vectored viruses to be an issue in spring watermelon production (and
other cucurbits) in South Florida.
While there is no way to know if the will
be a problem, growers are advised to scout fields for whiteflies and
virus.
Management practices:
Be alert for and eliminate cucurbit weeds
around melon fields.
Use a soil-applied neonicotinoid
insecticide such as imidacloprid (Admire®), thiamethoxam (Platinum®), or
dinotefuran (Venom®) should be used at planting for longer season cucurbits,
such as watermelon and calabaza, and possibly for green beans (imidacloprid
only).
If a foliar application of a neonicotinoid
insecticide such as acetamiprid (Assail®), dinotefuran, or thiamethoxam
(Actara®), is used instead of a soil application, it is best to apply it in the
first 30 days of the crop, before flowering (pollinator protection).
Switch to non-neonicotinoid insecticide
classes after flowering, and do not use any neonicotinoid class insecticides
for the remaining cropping period.
Spiromesifen (Oberon®) is effective against
immature stages of the whitefly.
IGRs - (buprofezin (Courier ®),
pyriproxyfen (Knack®) to control nymphs may be effective.
See Recommendations for Management of
Whiteflies, Whitefly-Transmitted Viruses, and Insecticide Resistance for
Production of Cucurbit Crops in Florida - http://edis.ifas.ufl.edu/in871
Efficacy Table for Single Mode of Action
Insecticides and Miticides Labeled for Cucurbit Vegetables in Florida - https://www.scribd.com/document/341391847/Efficacy-Insecticides-Cucurbits-003
Corn leaf blight
Growers and scouts in the EAA are seeing
low levels of both northern corn leaf blight in sweet corn.
Northern corn leaf blight caused by the
fungus Exserohilum turcicum.
Initial symptoms of the NCLB include yellow
spots that develop on the foliage.
These enlarge to form tan or straw-colored dead areas about 4 to 6
inches long and one half inch wide. NCLB produces a long, elliptical lesion,
while those of southern corn leaf spot tend to be oblong and much smaller than
those produced by NCLB.
Lesions caused by southern corn leaf blight
are much smaller (up to ½ inch wide and 1-inch-long) than those caused by
northern corn leaf blight. SCLB blight lesions are also lighter in color
(light tan to brown), and have parallel sides rather than the tapering sides of
lesions caused by E. turcicum.
Northern corn leaf blight, like southern
corn leaf blight, moves from the lower canopy to the upper canopy. Fungal
sporulation may be observed with a hand lens on foliar lesions following
periods of high humidity. When severe, lesions may become so numerous that they
coalesce and turn the entire leaf necrotic.
Bean Rust
Reports from the Glades indicate that mostly
low levels rust are becoming common in susceptible beans varieties.
Initial signs of bean rust on common bean
include fungal sori, seen as small white specks under the leaf epidermis, and
rust colored pustules. These pustules are found mainly on the underside of
the leaf and are often surrounded by a chlorotic ring.
Gene
McAvoy
Gene McAvoy
County Extension Director / Extension Agent IV
Regional Specialized Agent - Vegetables/Ornamental Horticulture
Hendry County Extension Office 863-674-4092 phone
PO Box 68 863-673-5939 mobile
LaBelle, Florida 33975 863-674-4637
fax
Web:
http://hendry.ifas.ufl.edu/ GMcAvoy@ifas.ufl.edu