How much things have changed

since our last bimonthly newsletter

went out! Hopefully much of these

issues are going to be behind us

soon, with Governor DeSantis issu-

ing Florida’s initial plan on returning

back to normal we’re all doing our

best to adapt while ensuring we con-

tinue to protect ourselves and our

neighbors. With the COVID issues

upon us extension had to make a lot

of changes rapidly in order to contin-

ue serving our client, hopefully many

of you were able to partake in the

numerous online programs offered

by all of our staff, from virtual in

home cooking demonstrations, virtu-

al 4-H, video horticulture consulta-

tions, and a range of gardening top-

ics being offered during the last two

months. For the near future we’re

going to be continuing with this vir-

tual programing to offer the most to

all of you; and perhaps this type of

training may become part of our

mainstay approach to increasing our

reach to the community. Things are

liking going to be in flux for a while

as we start transitioning back but re-

member we’re always here for you.

I hope you enjoy this edition of the

newsletter; as always we have some

interesting topics that can likely help

you correct or understand what

you’re seeing in your own yards!

In this Issue

Title Page

Leaf Wetness .................. 2

Spanish Moss ................. 3

Tomato Trouble ............. 4

MG Book Club .............. 5

Distance Education ........ 6

What to Plant ................. 6

“What’s That” Answer .. 6

For more information contact: UF/IFAS Extension Duval County

Chris Kerr - CKerr@coj.net - (904) 255-7450

Extension Update by Chris Kerr

Volume 2, Issue 3 May-Jun 2020

LARVAE

What’s That? Night Flying Adult Caterpillars in Squash Damage to Flowers

2

Leaf Wetness

Lawn diseases are a constant

issue that we have to deal

with to ensure our lawns re-

main at their peak. The

problem is so many home-

owners unknowingly are

putting their lawns into

harms way through their irri-

gation practices. I know for our

winter edition we discussed cali-

brating our lawn sprinklers, so if you haven’t read

that be sure to go back and incorporate that infor-

mation into your lawns cultural management pro-

gram.

Leaf wetness can be caused by several different fac-

tors including rainfall, dew, and overhead irrigation;

it’s basically the presence of water on the leaf’s sur-

face which is subsequently available for other organ-

isms to use. Those other organisms quite often in-

clude fungi and bacteria, but also many of our lawn

pests will benefit from this as well. The longer that

free water is present, the greater the chances of dis-

eases taking hold of the lawn.

The leaves are invariably going to get wet, but that

isn’t the crux of the problem. The issue is control-

ling the duration of the leaf wetness. Particularly for

fungi (hint: which happen to be the most common

culprit of lawn diseases in our area) the duration of

leaf wetness controls infective spore germination and

fungal growth. Each disease has a particular temper-

ature range and leaf wetness duration requirement for

infection to proceed. So anything we can do to re-

duce the leaf wetness duration will help to improve

the overall outcome.

We obviously can’t control the

rainfall, but what about dew?

While we might not be able to

easily control the formation of

dew, we actually can time our

irrigation to overlap the period

when dew is present. When

timed properly, the end result

actually produces larger water droplets

which roll off the leaves and reduces

leaf wetness durations. Following UF/IFAS irriga-

tion guidance, and your local irrigation ordinances,

are a great way to start managing lawn diseases be-

fore they even start. Irrigate on your assigned days,

no more than twice a week at 1/2” to 3/4” of water.

Water early in the morning while the dew is present,

if you water after this time you’re only extending

that leaf wetness duration, not to mention loosing

more water through evaporation. Here’s a quick

look at the seasonality and leaf wetness requirements

of some common lawn diseases:

Additional Reading:

Frequency of Residential Irrigation Maintenance Problems: (https://edis.ifas.ufl.edu/ae472)

Florida Turfgrass Irrigation Series: (https://edis.ifas.ufl.edu/topic_series_florida_turfgrass_irrigation_requirements)

Around the Yard by Chris Kerr

Above: Wet leaves promote fungal

disease in the lawn! (Photo UF/IFAS)

Disease Avg. Season Leaf Wetness Duration

Fairy Ring Feb. - Nov. Abundant Moisture

(High Organic Matter)

Large Patch Sep. - Apr. 48 hours

Take-All

Root Rot Apr. - Oct.

Abundant Moisture

(Over Irrigation)

Gray Leafspot May - Sep. 12 hours

(High Nitrogen)

Dollar Spot Sep. - Mar.

10 hours

(Low fertility, inadequate

irrigation)

3

Out on a Limb by Larry Figart

Spanish Moss- Friend or Foe:

Over the years, one of the most consist-

ently asked questions I have received

has to do with Spanish Moss. Does it

hurt the tree, and how can one get rid of

it. My answer is almost always the same

Spanish Moss Tillandsia usneoides, has

been co-existing with trees since the

dawn of time. Look at the image to the

right. It is the often photographed drive

to Wormsloe Plantation. Imagine the

image without Spanish moss? Now that

I think about it, that is probably too flip-

pant of an answer. There is probably a better way to

answer those questions.

Before we do that, lets look at Spanish moss a little

more closely. First, it is not a moss it is an epiphyte

(air plant) in the pineapple family. An epiphyte gets

its water and nutrients from the air, debris, and rain-

fall. If you look at Spanish moss under magnifying

lens you will see tiny scales. This is what it uses to

capture water and nutrients. You will not notice any

roots on Spanish moss. It does not have any. It simp-

ly hangs on trees and other things like utility wires.

Birds and wind spread small fragments of Spanish

moss. When the fragments land on a surface they

can cling to, they will continue to grow.

Spanish moss has a lot of uses. In the early 1900’s it

was used to stuff mattresses and cushions. The Great

Fire of 1901 in Jacksonville was started from a spark

that caught fire to Spanish moss on drying racks at a

mattress company near the corner of Davis and Bea-

ver Streets. In addition to stuffing mattresses it was

used as a binder for bricks.

Spanish moss is also utilized by wildlife. Bats roost

in clumps of Spanish moss. In addition to using

Spanish moss as nesting material, birds such as the

yellow throated warbler make their nests within the

hanging strands.

Now back to the tree question. Since it has no roots,

the Spanish moss is simply using the tree for support.

Most of the time that causes no harm to the tree.

What usually generates the call about Spanish moss

is the situation similar to the tree below. It is an old-

er crape myrtle. It is declining and the foliage is

thinning out. This gives the Spanish moss that has

blown from the oak behind it a perfect place to thrive

in the full sun. In a case like this I would say that the

moss is an aes-

thetic problem as

well as hamper-

ing the trees abil-

ity to recover. In

a tree that is still

a viable tree, re-

moval of the

moss would be

an option to con-

sider. When re-

moving moss,

the best way is to

pull it off. I have

seen folks use

rakes, pruning

saws, as well as broomsticks with nails hammered

into the end. For large trees consider using an arbor-

ist. There are some copper based products that have

labels for Spanish moss control. However the dead

moss will still need to be removed. If you use one of

those products read the label thoroughly before mix-

ing and applying. In the long run mechanical remov-

al is usually still the best option.

Photo by L. Figart UF/IFAS

Photo by L. Figart UF/IFAS

4

Growing in the Garden by Beth Marlowe

Tomato Trouble: Blossom End Rot

If the bottom end of the tomato (the one

that’s not attached to the plant) is turning black but the

rest of the tomato looks fine, you may have blossom

end rot (BER). This is not a disease, and it is not

caused by an insect pest. It happens when not enough

calcium has been making its way with water up from

the roots to the developing fruit. Lack of calcium

causes cell walls in the fruit to break down, leading to

invasion by a secondary pathogen. BER can also af-

fect peppers and cucurbit crops so if you’re growing

either of those pay attention to these potential issues as

well. Once you have BER on a fruit, that one can’t be

fixed. You can, however, prevent most cases of BER

through sound management practices.

You may think this means you simply

need to add more calcium to the soil to solve the prob-

lem. Although this may be a solution to the problem,

especially in a raised bed or container, our native soils

often have plenty of calcium. And our irrigation water

often has more. So how can there be a deficiency in

the fruit? There are three main causes:

1. Inconsistent watering. Calcium is transported up

through the plant in water. If watering is erratic,

then supplies of calcium to the developing fruit are

also erratic and may be missing when needed.

2. Over-application of nitrogen. Excessive nitrogen

can cause excessive leaf growth, redirecting water

(and calcium!) from the developing fruit to the

leaves. The ammonium form of nitrogen can also

inhibit calcium uptake.

3. Unavailability of soil calcium. This can be due to

an excess of soil magnesium or potassium, lack of

adequate or soil moisture to move the calcium, or

even damage to the root tips that take it up.

Once BER is apparent, solutions are

limited. You can try adding calcium to the soil, but if

lack of soil calcium was not the problem, adding more

will not fix it. Applying calcium solutions to the

leaves is generally more effective at preventing BER in

these situations, however it still won’t help correct any

damage that has already occurred. Harvest the dam-

aged fruit and change cultural practices going forward.

Water consistently. Add mulch to help soil retain

moisture. Get soil nutrients tested and amend or re-

duce fertilizer applications. Avoid damaging roots.

Blossom end rot is definitely a case where an ounce of

prevention is better than a pound of cure!

Photo Credit: nwdistrict.ifas.ufl.edu

Additional Resources:

Blossom End Rot in Bell Pepper: (https://edis.ifas.ufl.edu/ss497)

Tomato Disease in Florida Vegetable Gardens: (http://edis.ifas.ufl.edu/pp121)

Landscape and Vegetable Garden Test Form (http://edis.ifas.ufl.edu/ss187)

5

JOIN US!

MASTER GARDENER VOLUNTEER BOOK CLUB!

Who: You! The program is brought to you by the

Florida Master Gardener Volunteer (FLMGV)

program, but anyone can participate.

What: We’ll be reading The Foodscape Revolution, by

Brie Arthur. Foodscaping means incorporating

edible plants into your existing home land-

scape.

When: Begin reading now. The FLMGV Program will

host a webinar to discuss in May. Check the

Duval County Extension website or FLMGV

social media channels for the exact date.

Where: Join us online from the comfort of your own

home.

Why: It’s a great way to connect with other garden-

ers from all over the state who are interested in

growing more food at home!

How: Simply purchase or borrow the book and follow

us on Facebook or Instagram. See the blog at http://blogs.ifas.ufl.edu/

clue/2020/04/17/announcing-the-florida-master-gardener-volunteer-book-club/

for more details.

Images courtesy FLMGV Program

6

Distance Learning Resources

Virtual Vegetable Gardening Series

Fridays, April 3 - June 5, 2 p.m. - 3 p.m. Stuck at home and looking to grow more of your own food? This is an excellent introductory course on a range of vegetable gardening topics, access via Zoom for free from the comfort of your own garden! https://www.eventbrite.com/e/101647614752

4-H Virtual Embryology

May 13 - June 3 Receive access to daily videos with updates on chick embryo development, vo-cabulary, science experiments to try at home, and other hands-on activities. There will also be a live stream of chickens hatching! 4-H Membership is NOT required, all are welcome to participate at no cost. Program is geared towards K-5 students but additional resources are available for grades 6-8. https://www.eventbrite.com/e/102888014822

Lawn Management Webinar Series

Friday May 15 and May 22, 11:30 a.m. to 1:15 p.m. Maintaining a healthy vibrant lawn isn’t always easy, but it shouldn’t be difficult either. Learn about a range of topics related to lawn care including the selection, identification and cultural management of turfgrasses, chemical considerations, damaging lawn pest and diseases of the Florida lawn. https://www.eventbrite.com/e/104144769810 Don’t forget UF/IFAS has a lot of gardening resources available online including: Extension Electronic Data Information Source: https://edis.ifas.ufl.edu UF Entomology Featured Creatures: Entnemdept.ufl.edu/creatures Need to find a UF Expert? : https://ics.ifas.ufl.edu/experts/

It’s the pickleworm! This is a very common pest in the backyard garden on a range of cucurbit crops including cucumbers, squash, cantaloupe, pumpkin and watermelons among others. This one can be a bit more difficult to control than some of our other common pests if we’re not paying close attention and scouting regularly. The issue is, the pickleworm feeds internally, so most of our chemical and biological controls are less effective. In fact, for products such as Bt.to be effective, you’ll have to start regular applications at first bloom through har-vest. Some of the thicker rind curcurbits can fair better once the rind thickened but these caterpillars often start by attacking the blooms and then burrowing into the fruit before the blossom drops. They can feed rather dis-cretely and cutting into your vegetables later can lead to a big surprise. Their feeding will quickly render those vegetables in-edible. Another option for small plantings is to cover them with a raised netting at night, the adults only fly at night so this can limit their ability to lay eggs, just remember to remove the netting in the morning so pollinators can reach the flowers.

Further Reading:

Pickleworm, Diaphania nitidalis (Stoll): (https://edis.ifas.ufl.edu/in321)

What to Plant in

May & June

It’s starting to get hot so

make sure you’re using

plants that can handle our

Florida weather.

Annuals - Angelonia, celo-

sia, coleus, portulaca, sal-

via, ornamental peppers,

vinca and wax begonia.

Bulbs - Daylily.

Vegetables - Okra, south-

ern pea, sweet potato and

swiss chard.

Herbs - Basil, oregano, tar-

ragon, rosemary.

Keep monitoring those

pests populations and im-

plement appropriate con-

trols! Don’t forget to put in

some floral nectar sources

to encourage the beneficial

insects!

What’s That?