In the beginning, thousands of years ago, there was only

one mole cricket species in Florida: Neocurtilla hexadactyla

ENY 5241 Biological control – biological control of mole crickets

(Gryllotalpidae)

but there were 80+ species elsewhere in the world

northernnorthern mole cricketmole cricket

It was not a problem because:

(a) it preferred heavy soils(b) there was little agriculture(c) its populations were regulated by two specialist natural enemies: Larra analis and Steinernema neocurtillae as well as generalist natural enemies (hawks, owls, tiger beetles, ground beetles, spiders, etc.).

native wasp native wasp Larra Larra analisanalis

In the very early 1900s, farmers in In the very early 1900s, farmers in southeastern Georgia were beset by a southeastern Georgia were beset by a new problemnew problem

mole cricket galleries in a mole cricket galleries in a seedling bedseedling bed

So they blamed mole crickets. But native mole crickets were not known to do such things, so these must be foreign mole crickets. Where did they come from? Maybe Puerto Rico, where mole crickets had caused problems for decades? So they called what they had “the West Indian mole cricket.”

but they were wrong – due to lack of taxonomy

They were wrong because this was not the mole cricket that caused problems in Puerto Rico – it was worse. “It” was, in fact, three species:

Scapteriscus abbreviatus (short-winged m.c.) Scapteriscus borellii (southern m.c.) Scapteriscus vicinus (tawny m.c.)

They had all arrived from southern South America as hitchhikers in ships’ ballast (they were not “introduced” - nobody in their right mind would have “introduced” them). They were adventive, meaning “they had arrived” and they spread south to Florida, west, and north.

Mole cricket damage to a golf courseMole cricket damage to a golf course

Then they began to attack turf on golf coursesThen they began to attack turf on golf courses.

Mole cricket damage to a pastureMole cricket damage to a pasture

And began to attack pasturesAnd began to attack pastures

What did people do?Used chemical pesticides

1. from the time that South American pest mole crickets first became a problem in Georgia and Florida, people bought and applied chemical pesticides against them

2. but chemical pesticides CANNOT provide a permanent solution – we have >100 years of evidence of this – unfortunately, too many people have a “pesticide mentality”

in 1978 the Florida Legislature earmarked some UF/IFAS funds for a mole cricket research program… to benefit ranchers

chlordane was used in Florida pastures to kill mole crickets from the 1940s until this material was banned in the 1970s by the EPA

•

After 12 months of this program with earmarked state funds, Dr Tom Walker became coordinator (in 1979)

With him worked Drs Drion Boucias, Reece Sailer, and Grover Smart

Later, with funds from a grant obtained by Dr Walker, a postdoc (Harry Fowler) was hired – he was sent to South America to explore for potential biocontrol agents – and a contract was given to a collaborator (Dr Aquiles Silveira Guido) to do the same in Uruguay.

In 1985, Howard Frank took over from Tom Walker as project coordinator (someone has to do the paperwork) Fred Bennett joined the program (fall 1985) Reece Sailer retired Drion Boucias left the program (when there were no funds) Fred Bennett retired (summer 1993) Grover Smart retired from research Tom Walker retired Howard Frank was the only faculty member left

postdoc Will Hudson (1985-1988) was succeeded by postdoc Pat Parkman (1988-1996) – then there were none

UF/IFAS mole cricket research program 1978-present

• Annual meeting 1978-1995 in the Entomology/Nematology Department • Annual research reports 1979-1995• Mole crickets in Florida (Bulletin) 1985 • MCRICKET (website) 1996 http://entnem.ifas.ufl.edu/fasulo/molecrickets/• 11 MS theses, 7 PhD dissertations, 140+ papers in scientific journals

• since the 1980s has maintained a culture of shortwinged mole crickets for research

UF/IFAS mole cricket research program 1978-present

Investigated• Taxonomy and origin of mole crickets• Life cycles and behavior

• Sampling methods and ecology

• Physiology and pathology

• Biological control

•

UF/IFAS mole cricket research program 1978-present

• realized that pesticides are not the answer to ranchers’ needs, but “bought time” by developing a user-formulated bait

• realized that classical biological control might be able to solve the problem permanently throughout Florida –

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3 release of one or more effective classical biocontrol agents

northernnorthern mole cricketmole cricket

1. generalist natural enemies such as owls, armadillos, spiders, and tiger beetles 2. specialist natural enemies such as the wasp Larra analis and the nematode Steinernema neocurtillae

The northern mole cricket is native to the eastern USA and

is attacked and killed by:

short-winged mole cricketshort-winged mole cricket

southern mole cricketsouthern mole cricket

•

tawny mole crickettawny mole cricket

1. Why? Because the South American invader mole crickets (genus Scapteriscus) are NOT closely related to the northern mole cricket (genus Neocurtilla)

2. What to do? Find and import specialist natural enemies of the South American invader mole crickets

BUT the specialist natural enemies did NOT attack the South American invaders

1. the wasp Larra bicolor

3. the beetle Pheropsophus aequinoctialis2. the fly Ormia depleta

4. the nematode Steinernema scapterisci

Four biological control agents were brought to Florida from South America by the UF/IFAS mole cricket research program in the 1980s

imported wasp imported wasp Larra bicolorLarra bicolor

3. spread to neighboring counties – and has now been detected in >46 counties

2. was released in Alachua County

1. was introduced from Bolivia in the 1980s

the wasp Larra bicolor

imported fly Ormia depleta

1. was introduced from Brazil in the 1980s

2. was released in Alachua County – - and many other counties

3. Now occupies 38 counties –- from Alachua southward

the fly Ormia depleta

larva of beetle Pheropsophus aequinoctialis

with mole cricket eggs

1. was brought to quarantine in Gainesville from Uruguay and Brazil in the 1980s, then from Bolivia in 1993

2. has not yet been released – some graduate students have worked on it, but research is difficult and is incomplete

the beetle Pheropsophus aequinoctialis

dead mole cricket with emerged dead mole cricket with emerged nematodesnematodes

1. was introduced from Uruguay in 1985

3. was mass-produced by industry on an artificial diet, and sold as a biopesticide

2. was released in Alachua County in 1985, and spread in that county

4. experimental releases and commercial sales spread it to other counties

the nematode Steinernema scapterisci

☺ so, Howard Frank, co-ordinator of the program, 1985-present, chose to emphasize the work on Steinernema scapterisci – simply because it was likely to be completed sooner – not because the nematode was “better” - and let the work on the wasp, fly, and beetle wait until later

Even in 1989, funds of the UF/IFAS mole cricket research program were not generous – they were not enough to allow full-scale research on the wasp, fly, beetle, and nematode all at the same time

Steinernema scapterisciSteinernema scapterisci was applied was applied to 2.5-acre plots in pastures in 6 to 2.5-acre plots in pastures in 6 counties in 1989, in a 2-year trial – it counties in 1989, in a 2-year trial – it established permanent populations established permanent populations that spread to nearby areasthat spread to nearby areas

1. wasp-farming (like butterfly-farming): we must learn how to enhance populations of Larra bicolor where we want its services 2. we are checking the prey-specificity of the beetle Pheropsophus aequinoctialis before applying for a release permit

3. we learned that adults of the fly Ormia depleta need insect honeydew for energy – now we must learn how to farm them

Research in progress

Spermacoce verticillata (a wildflower)

provides nectarto the adult wasps

1. we would like to get this research finished last year, but …

2. we have funding problems – and even entomology graduate students have to eat – the State appropriation for mole cricket research that allowed all that research and importation in the 1980s got “un-earmarked” in 1991 ☹☹

Why can’t we speed up the research – get it done faster?

the program operated traps nightly the program operated traps nightly for 25 years near Gainesville to for 25 years near Gainesville to measure changes in mole cricket measure changes in mole cricket populationspopulations

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-- mole cricket levels since 1992 have fallen to 5% of what they were in the 1980s as judged by total annual catch in traps-- this is a huge success that now we need to spread throughout Florida

area-wide biocontrol

soDue to continual action of two of the biological control agents (the wasp and the nematode) in the Gainesville area --

1. the beneficial nematode Steinernema scapterisci – which was produced and marketed as a biopesticide called Proact (later Proactant) in 1992-1996 … is being produced again, by a different company (Becker-Underwood), under the trade name Nematac S

2. it is best that you do not think of it as a pesticide – think of it as a way to get an area-wide biocontrol agent established

and meanwhile

The program had to become involved in considerable educational (extension) effort because of the expectations of the two main beneficiary groups.

Neither group really understood mole crickets, and knew nothing about biocontrol agents.

Ranchers expected to use a chemical, perhaps in a bait, and to see dead mole crickets on the soil surface. They thought $5/acre was a reasonable price to pay for such a material.

Golf course superintendents had zero tolerance for mole cricket galleries on tees and greens. They were willing to spend much more, and they, too, expected to see dead mole crickets on the soil surface.

They did not see wasps or flies or nematodes, so they doubted the presence of the biocontrol agents.

Mole crickets killed by the biocontrol agents seldom died at the soil surface, so neither group had any good way of verifying that the biocontrol agents were present or had any effect. The beneficiaries had no long-term records, e.g., of how things were 10 years ago.

Unlike chemicals, the biocontrol agents reduce mole cricket populations slowly, making the action even harder to detect. There was scepticism.

More effective, new chemicals came on the market and were promoted heavily to the turf industry.

Beneficiaries had a difficult time comprehending that the biocontrol agents provide permanent, area-wide suppression – this did not fit the mold of chemical pesticides, whose effects are limited to the place of application.

One place where it has been evident is the lawn-care industry in the Gainesville area. Here, there is very little call any more to treat lawns with insecticides against mole crickets. That industry still has plenty of business applying fertilizers and herbicides.