Pick up know-how for tackling diseases, pests and weeds.
Farm bill, farm marketing, agribusiness webinars, & farm policy.
Find tactics for healthy livestock and sound forages.
Scheduling and methods of irrigation.
Explore our Extension locations around the state.
Commercial row crop production in Arkansas.
Agriculture weed management resources.
Use virtual and real tools to improve critical calculations for farms and ranches.
Learn to ID forages and more.
Explore our research locations around the state.
Get the latest research results from our county agents.
Our programs include aquaculture, diagnostics, and energy conservation.
Keep our food, fiber and fuel supplies safe from disaster.
Private, Commercial & Non-commercial training and education.
Specialty crops including turfgrass, vegetables, fruits, and ornamentals.
Find educational resources and get youth engaged in agriculture.
Gaining garden smarts and sharing skills.
Creating beauty in and around the home.
Maintenance calendar, and best practices.
Coaxing the best produce from asparagus to zucchini.
What’s wrong with my plants? The clinic can help.
Featured trees, vines, shrubs and flowers.
Ask our experts plant, animal, or insect questions.
Enjoying the sweet fruits of your labor.
Herbs, native plants, & reference desk QA.
Growing together from youth to maturity.
Crapemyrtles, hydrangeas, hort glossary, and weed ID databases.
Get beekeeping, honey production, and class information.
Grow a pollinator-friendly garden.
Schedule these timely events on your gardening calendar.
Equipping individuals to lead organizations, communities, and regions.
Guiding communities and regions toward vibrant and sustainable futures.
Guiding entrepreneurs from concept to profit.
Position your business to compete for government contracts.
Find trends, opportunities and impacts.
Providing unbiased information to enable educated votes on critical issues.
Increase your knowledge of public issues & get involved.
Research-based connection to government and policy issues.
Support Arkansas local food initiatives.
Read about our efforts.
Preparing for and recovering from disasters.
Licensing for forestry and wildlife professionals.
Preserving water quality and quantity.
Cleaner air for healthier living.
Firewood & bioenergy resources.
Managing a complex forest ecosystem.
Read about nature across Arkansas and the U.S.
Learn to manage wildlife on your land.
Soil quality and its use here in Arkansas.
Learn to ID unwanted plant and animal visitors.
Timely updates from our specialists.
Eating right and staying healthy.
Ensuring safe meals.
Take charge of your well-being.
Cooking with Arkansas foods.
Making the most of your money.
Making sound choices for families and ourselves.
Nurturing our future.
Get tips for food, fitness, finance, and more!
Understanding aging and its effects.
Giving back to the community.
Managing safely when disaster strikes.
Listen to our latest episode!
by Aaron Cato - July 29, 2022
We still haven’t observed any Melonworm in the state this year, but we are on the
lookout and will be posting on our Facebook, Twitter, and Blog when they finally show up. To avoid the levels of damage to handles and rinds that
we saw last year we need to be considering insecticide applications as soon as the
moths show up.
In addition to the recommendations below, please consult the Southeastern Vegetable IPM Handbook for more guidance. If you have any questions about symptomology on your pumpkins,
contact your county agent to get samples sent to Sherrie Smith at the Plant Health Clinic for identification.
We’ve seen less cucumber beetles this year compared to the last and it seems it has
something to do with the early heat. Squash bugs don’t seem to mind the heat as much
and have been around in summer squash all year and now are getting into pumpkins.
These two pests are generally considered the most serious pumpkin insect pests in
Arkansas as they transmit bacterial diseases. These diseases are well known by most
of our growers and typically lead to many unnecessary over-sprays, however, both pests
are very easy to scout for and these diseases can be prevented if insecticides are
on-time. Outside of our disease-causing pests, melonworm is the most serious pest
and widespread damage was observed across the entire state and MidSouth in 2021. We
don’t see those levels of damage every year and we need to be on the lookout for moths
and larvae to prevent major losses.
Spotted and striped cucumber beetles are known to be an issue in Arkansas and can
transmit bacteria that can cause bacterial wilt (Fig. 1 and 2). Adults feed on the foliage, flowers, and on the surface of the fruit, and plants
are susceptible to wilt transmission as soon as they emerge or are transplanted. Younger
plants (before 4-leaf) are most susceptible to the disease, therefore scouting twice
a week is necessary early on. Thresholds depend on the type of cucurbit you are trying
to protect and the age of the planting. An insecticide application should be made
to pumpkins when 1 cucumber beetle is found every plant on average until plants have
5 true leaves. After this growth stage an application should be made when populations
reach 4-5 beetles per plant on average. Cucumber beetles are known to migrate into
fields quickly, which warrants frequent scouting. This is especially important after
an insecticide application is made, as re-infestation at densities above threshold
is possible in only a few days.
Many insecticides can be used to manage cucumber beetles, but considering that most
can flare aphids, scout to make sure applications are necessary. Effective insecticides
include pyrethroids (IRAC 3A - bifenthrin, lambda cyhalothrin, etc.), neonicotinoids
(IRAC 4A - imidacloprid, acetamiprid, dinotefuran, thiamethoxam, and clothianidin),
carbamates (IRAC 1A - carbaryl), and organophosphates (IRAC 1B - malathion). Neonicotinoids
such as imidacloprid and dinotefuran can also be applied as drip applications and
may provide some aphid and squash bug suppression. If you didn’t use a neonicotinoid
drip application at planting and are seeing high numbers of cucumber beetles, I recommend
getting out an imidacloprid application (soil only) ASAP to help rotate effective
insecticide mode of action (MOA – IRAC Code). If populations are excessive, use a
knockdown foliar insecticide even when you still expect protection from a systemic
drip applied insecticide.
Fig. 1 – Spotted and striped cucumber beetles. Photo courtesy of Ric Bessin, Univesity of
Fig. 2 – Bacterial wilt disease symptomology.
Like cucumber beetles, squash bugs are an issue as soon as plants are in the field
and can vector bacteria that cause cucurbit yellow vine disease, also known as yellow
vine decline (Fig. 3, 4, and 5). Smaller fields are most susceptible, and numbers generally are the highest on field
edges and during fruit-set and bloom. Fields should be monitored at least once a week
and monitoring should be focused on the underside of leaves, at the base of plant,
and under fallen leaves where squash bugs often congregate. Adults are difficult to
manage and applications should target young nymphs or eggs. Apply an insecticide when
egg masses or nymphs are observed on every few plants. Effective insecticides include
pyrethroids (IRAC 3A - bifenthrin, lambda cyhalothrin, etc.), neonicotinoids (IRAC
4A - imidacloprid, acetamiprid, dinotefuran, thiamethoxam, and clothianidin), and
carbamates (IRAC 1A - methomyl). Neonicotinoids such as dinotefuran and imidacloprid
(soil only) can also be applied as drip applications and may provide some aphid and
cucumber beetle suppression.
Fig. 3 – Squash bug adult pictured on a summer squash leaf.
Fig. 4 – Squash bug eggs pictured on top of a pumpkin leaf.
Fig. 5 – Yellow vine disease symptoms pictured on a pumpkin plant in Arkansas.
Melonworm, Diaphania hyalinata, is a pest of pumpkins that feeds just under handles and etches the rind of pumpkins.
There is a lot of confusion as to what pest species we are seeing in Arkansas pumpkins
with names such as “rindworm” or “pickleworm” being used. Pickleworm is a different
species, Diaphania nitidalis, and not one that we will talk about much considering it is less common. Much of
this confusion comes from the sporadic nature of this pest and how quickly damage
can sneak up on growers.
Melonworm is a tropical moth species (Fig. 6) which migrates to Arkansas from coastal regions in August-October, with arrival times
varying from year-to-year which makes timing of management very difficult. Larvae
are green caterpillars with two longitudinal, white stripes down their back (Fig. 7). Larvae will quickly defoliate leaves of pumpkin plants and leave a “skeletonized”
appearance with only the leaf veins remaining (Fig. 8). You can often find larvae hiding under rolled, or turned pumpkin leaves as seen in
fig. 8. Melonworm larvae can quickly burrow into the rind of the pumpkin and under
the stem/handle which causes the stem to fall off (Fig. 9). Feeding on the rind results in the fruit ultimately becoming unmarketable.
Melonworms don’t overwinter in Arkansas so its arrival each year depends on the climatic
conditions for the year. In 2021 moths showed up much earlier than previous years
and began multiplying rapidly before pumpkin harvest started. Significant damage was
easy to see at many commercial pumpkin operations across Arkansas by late September.
The occurrence of moths should be an early sign for growers that an insecticide application
may be necessary. If growers can easily find these white and brown moths flying in
plantings, or are seeing larvae on leaves, a pesticide application will be necessary.
A threshold for this pest doesn’t currently exist and research in Arkansas Is ongoing.
Many effective products for melonworm are available but effective residual control
for each product will lead to more or less favorable results. Caterpillar specific
products containing chlorantraniliprole (IRAC 28 - Coragen), cyantraniliprole (IRAC
28 - Exirel), or cyclaniliprole (IRAC 28 - Harvanta) will offer the longest residuals
and should provide at least 21 days of residual control. Other caterpillar specific
products such as spinetoram (IRAC 5 - Radiant) and methoxyfenozide (IRAC 18 - Intrepid)
and also broad-spectrum insecticides such as pyrethroids (IRAC 3A - bifenthrin, lambda
cyhalothrin, etc.) will provide around 1 week of control. These insecticides should
be reapplied in 7 days if moths or larvae are still being observed.
Fig. 6 Melonworm moth on a mature pumpkin. These moths are easily observed on fruit or leaves
during daytime hours and are easily disturbed.
Fig. 7 – Melonworm caterpillars present on the underside of a pumpkin leaf. These larvae
can be identified by their green color and the two white stripes on their back.
Fig. 8 – Feeding damage caused by melonworm which is usually characterized by “skeletonized’
leaves that only have veins remaining (pictured right) or by rolled leaves (pictured
Fig. 9 – Melonworm larvae feeding just under the handle/stems of pumpkins. Look for webbing
or excrement, as shown in this picture, as an indication that larvae are feeding underneath.
Melon aphid, Aphis gossypii, is considered a secondary pest in Arkansas pumpkin production. Insecticides such
as pyrethroids, pyrethrins, carbamates, or organophosphates that are used to control
cucumber beetles, squash bugs, and other pests, kill the natural enemies that usually
keep aphids suppressed. If you have used broad-spectrum insecticides in your pumpkin
patch this year, including many organic options, then you need to be scouting for
aphids (Fig. 10). There are many product options for aphid control such as acetamiprid (IRAC 4A- Assail,
Tristar, and Anarchy), flupyradifurone (IRAC 4D - Sivanto Prime), sulfoxaflor (IRAC
4C - Transform), and Flonicamid (IRAC 9C - Beleaf). Acetamiprid, sulfoxaflor, or flupyradifurone
are likely going to be the easiest products to find locally. Aphid control is necessary
when populations are building on every few plants and the natural enemy complex was
collapsed by recent broad spectrum insecticide sprays.
Fig. 10 – Melon Aphids on the underside of pumpkin leaves following a pyrethroid spray.
Many of the insecticides mentioned here will control both cucumber beetles and squash
bugs, and in most production areas of the state, these pests are likely to be present
at the same time. Due to the risk of flaring melon aphids, a good strategy is to start
early with a drip application of imidacloprid (Admire Pro) or dinotefuran (Venom or
Scorpion) to prevent flaring aphids. These products usually give at least 3 weeks
of suppression that should help protect from bacterial wilt or yellow-vine disease.
Foliar applications of pyrethroids are usually relied on for cucumber beetle and squash
bug suppression, but it is important to rotate in other Modes of Action like carbamates, neonicotinoids, or organophosphates where possible. Repeated use
of one chemistry is likely to lead to lowered success of control. This is especially
important when considering squash bug, as it is difficult to suppress this pest once
infestations are excessive.
Melonworm is not likely to be a serious pest every year, but the losses we incurred
last year are a stark reminder that we need to be scouting every week beginning in
August. Rely on diamide products (IRAC 28) like Coragen or Exirel once moths or larvae
are observed in fields. A second application may be necessary in 21 days if pumpkins
still need to be protected.