IPM OF MOLE CRICKETS WITH A COMBINATION OF NATURAL ENEMIES Howard Frank UF/IFAS Mole Cricket Research Program Entomology & Nematology Department University of Florida
why doesn’t the northern mole cricket trash turf throughout the eastern USA?
at least in part because it is attacked by a specialist native wasp, Larra analis and a specialist native nematode, Steinernema neocurtillae. UF/Choate
So, turf managers in the eastern USA don’t have to worry about the northern mole cricket - which is native to the USA. But in Brazil, where the northern mole cricket is NOT native, it has been claimed to cause damage.
Native insects may have specialist natural enemies (such as wasps and nematodes) that control them … free! But when insects arrive from abroad, they may become pests because their native natural enemies were left behind in their homeland.
“IPM strategies generally rely first upon biological defenses before chemically altering the environment.” part of President Carter’s 1979 Environmental Message
damage by pest (South American) mole crickets to a Florida golf course J.P. Parkman/UF
Ever since the tawny, southern, and shortwinged mole crickets arrived from South America (100 years ago), turf managers have relied primarily on chemical pesticides against them So, what happened?
What happened to the lesson just explained – that natural enemies can control them? What happened to President Carter’s message that“IPM strategies generally rely first upon biological defenses before chemically altering the environment.”
The specialist natural enemies were not here in Florida – they were in South America – and they needed research. The obvious answer was to bring them from South America and research them. They might provide free control of the pest mole crickets.
Four biocontrol agents were brought to Florida from South America by the UF/IFAS Mole Cricket Research Program in the 1980s 1. a wasp: Larra bicolor 2. a fly: Ormia depleta 3. a beetle: Pheropsophus aequinoctialis 4. a nematode: Steinernema scapterisci
The task since then has been to : • test whether they are safe for release (and, if they are): 2. spread them throughout Florida 3. learn how to enhance their populations locally where their services are needed Here’s where we are now:
from Bolivia 1988 the wasp Larra bicolor Present in at least the counties marked, and spreading in northern counties from Puerto Rico1981
the wasp Larra bicolor 1. was introduced from Bolivia in the 1980s 2. was released in Alachua County • 3. has spread to neighboring counties – • at least to Putnam, Clay, and Levy - maybe more
Spermacoce verticillata (a wildflower) provides nectar to the adult wasps Spermacoce verticillata (a wildflower) provides nectar to the adult wasps – it and other wildflowers perhaps can be used to enhance local populations of the wasp – like butterfly gardening UF/Choate
imported fly Ormia depleta UF/Castner
the 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 – is not spreading northward
larva of imported beetle Pheropsophus aequinoctialis with mole cricket eggs UF/Castner
the beetle Pheropsophus aequinoctialis 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 entomology graduate students have worked on it – but we need to be totally sure of its diet before a release permit can be issued
dead mole cricket with emerged Steinernema scapterisci nematodes UF/Nguyen
the nematode Steinernema scapterisci 1. was introduced from Uruguay in 1985 2. was released in Alachua County in 1985, and spread in that county 3. was mass-produced by industry on an artificial diet, and sold as a biopesticide 4. experimental releases and commercial sales spread it to many other counties
The nematode differs from the wasp and the fly in two ways: (1) it needs only mole crickets to survive (the adult wasp and adult fly need energy from nectar or honeydew) (2) it can be mass-produced and sold as a biopesticide (this is happening) This does not mean the nematode is a better biocontrol agent, just that it can be handled like a pesticide
The work has resulted in establishment of populations of the wasp and the nematode in the Gainesville area. Those two biocontrol agents together have reduced pest mole cricket numbers by about 95% in the Gainesville area since the 1980s
southern mole cricket, Gainesville biocontrol period
My vision is of the presence of good populations of at least two species of these biocontrol agents everywhere in Florida to provide statewide biocontrol At that point, heavy mole cricket damage will be a thing of the past
Pesticides (either chemical or biological) will be used against mole crickets just on golf course tees and greens. People will plant selected wildflowers to encourage local populations of the wasp and the fly. And control costs will be FAR less than at present.
It is important to remember that all four biocontrol agents are expected to contribute to permanent biocontrol of pest mole crickets And they don’t harm non-target organisms – not even the northern mole cricket
About 80% of the support for the UF/IFAS Mole Cricket Research Program came from UF/IFAS funds earmarked in 1978-1991 by the Florida legislature for this purpose, about 10% from the Federal government, and 10% (before 1992) from the turf industry. The research job is far from finished. It could be speeded if the research were better funded by the turf industry.