Purple Loosestrife

Part 2, 6 minutes.
Purple Loosestrife - Videos

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Music Now Purple Loosestrife is a pretty plant, but what it does to wetlands is pretty ugly. It chokes out most of the other vegetation around it. Every species has a role to play in nature. Just as human diversity is vital to social systems, biodiversity is vital to ecosystems. For example, Bee keepers love purple loosestrife because it provides lots of nectar for bees to make their honey. But ecologists don’t like it because it destroys biodiversity. Invasive species often take up so many resources that there aren’t enough left for the native species to survive. Scientists believe that purple loosestrife also came to the United States on a ship. This time the ship came from the Middle East and instead of insects hiding in the packing material there were probably just a few loose seeds sloshing around in the ships hull. When the bilge was pumped from the ship, plant material made its way to our shores and purple loosestrife thrives along American waterways.

On the IPM pyramid of tactics there aren’t any cultural approaches. Purple Loosestrife is already here, well established and growing in the wild. In terms of physical or mechanical controls such as weeding and burning, but this isn’t always a cost effective option since purple loosestrife lives off the beaten path. It’s sometimes tough to get to in remote or marshy areas. Chemical controls are a problem because loosestrife is usually so close to waterways. You always want to keep chemicals away from aquatic habitats and drinking water whenever possible. There are however some pretty decent biological controls available.

The purple loosestrife that you see behind me is a very invasive weed species that we’ve been battling in Pennsylvania for a number of years. It’s mainly a wetland area plant, but it has begun to move or encroach into agricultural land affecting crops. So one reason why my agency got involved with the bio-control for loosestrife is because of that encroachment in the cropland. In the purple loosestrife program, we have 3 different insects that we release in our biocontrol program. The major one is Galerucella. It is a leaf eating beetle, that we rear in laboratories in several locations in the US or else they are field collected. The collections are shipped over night through mail, kept in a cooler with a cold pack.

At that point we take them to specific sites that we’ve chosen because of the amount of loosestrife that’s present. We take these canisters of insects and we release them all onto the plants. They feed immediately and hopefully will begin breeding and reproducing. The goal is to establish what we call an insectary so that we can come back and harvest that particular beetle from the location and spread to other sites that do not have them.

(BugMobile) So how do you make sure you’re not using a bug that eats all kinds of plants?

The species that we use for the loosestrife program are very specific. For Galerucella and the other 2 that we utilize about 280 different species of insects were screened and tested to make sure that they did not feed on other plants. The three that we use that I mentioned are very specific to loosestrife and will not feed on any other plant that we know of. Biocontrol for my agency is one of the many tools that we use to help control invasive species. Biocontrol is one of those tools in which we release a good insect if you will, to combat a bad insect or weed in this case, as we are talking about purple loosestrife. It is not a cure all and it does not completely control a weed or a pest, but it is one of the tools that helps do so.

(BugMobile) So do the good bugs really do the trick?

The beetles that we are releasing on loosestrife have been effective, again being part of an IPM program, they are only effective to a certain degree. We have seen stands that are about 7 or 8 years old where we released beetles that many years back that have about a 25-35% control. Again, it’s other measures you have to use to completely get rid of loosestrife along with the biocontrol. (BugMobile) But doesn’t it get expensive having to buy and ship all those bugs?

My agency views biocontrol as an important tool because it’s an economical tool in a way. It does not completely control a pest or invasive species, but it is part of the complex that we use in an Integrated Pest Management system along with chemicals and cultural practices. The biocontrol fills in the gap. It’s long term and the insects will be out here for many many years doing their job. It helps to keep the population of weeds, such as purple loosestrife in check. (BugMobile) Cool, well thanks Gary. I like those beetles better than that longhorned fella. But if you turned me loose, I’m not sure I’d hang around a bunch of purple loosestrife. Give me the road anytime.

Beach boys music. Hey why so blue!!!! Hahah I love that joke!


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