Longview News Journal: Thursday, January 23, 2014

Giant salvinia is choking the lakes of East Texas. Plug “giant salvinia” into the mapping tool at texasinvasives.org and it shows 42 reported instances of the aquatic weed in Texas bodies of water, with all but one of those east of Huntsville.

The fast-growing plant is found on all our area lakes, including Lake ’O the Pines and, more seriously, Caddo Lake. Caddo, Texas’ only natural lake, has at times been rendered almost unnavigable because of giant salvinia.

The growth of salvinia has happened in spite of a vigorous and continuing attempt to stop the plant in its tracks. Just about every tactic imaginable has been used, from herbicide to mechanical harvesting. Little that has been attempted has worked for very long.

But now, Caddo’s Salvinia Action Committee is turning its sights to what could be a longer-term strategy to control, not eradicate, the invasive plant. The committee is significantly ramping up use of the salvinia weevil, the plant’s only natural predator.

The weevil has shown some success in the past but the number of the tiny insects applied to the lake has been limited. The new plan calls for raising 250,000 weevils this year from a base on the shores of Caddo Lake. That would be roughly five times what has been released the previous two years and the effort should have a major impact.

Another change in strategy is to forget the idea of eradicating giant salvinia. Those who have been fighting growth of the plant over the years realize that simply is not going to happen. The point now is to contain it. This makes sense and is a more realistic goal that can actually be attained.

An infestation can occur after a sprig on one boat trailer is accidentally transferred from one lake to another. With 42 infestations in Texas alone, the weed will certainly be reintroduced into lakes. So this is not a temporary project but an effort that must always be with us.

The Caddo Lake work is important because of the lessons it can impart about dealing with giant salvinia in other lakes. The effort here can lead the way to successful salvinia control becoming a standard procedure across Texas.

The Caddo Lake effort does not come without financial cost, though. There will be an annual operating expense of $130,000 to keep the weevil population growing. Some of that can come from private sources but some state or federal assistance is probably going to be needed. That should be put on the table for the next legislative budget. With all the odd expenses the state budget covers, surely lawmakers can find some money to protect the only natural lake of Texas.

Greater Caddo Lake Association of Texas

P.O. Box 339
Karnack, TX 75661