Stranger Danger

There are many pest issue that we are faced with out in the fields. Insects, weeds, diseases, and these all have many different kinds. There are many factors that influence how to deal with all these specific issues. But every once in a while something new come up that causes issue that well take the decisions you want to make out of your control. This is the threat of “Invasive Species”.

“An invasive species is a species that does not occur naturally in a specific area and whose introduction does or is likely to cause economic (including agricultural) or environmental harm or harm to human health.

These are usually species that we normally do not have in California and that countries we send our products too do not want either. These Exotic pests are organisms that are introduced into an area beyond their natural range and become pests in the new environment. They are also referred to as alien, non-native, or introduced pests. Most introductions have been unintentional and accidental. Having evolved in a different ecosystem, these non-native species may have few natural enemies in their new locations, which can often lead to population increases that can overwhelm native species by out-competing them for resources (e.g., food, water, light, space).” CDFA

Most of the invasive species I’ve had to deal with are insects, but they can be diseases, weeds and even other environmental problems such as fish or other animals. Insects are usually transported into the state on plant material from nurseries, food items, etc. With the mobile nature of our society, this is an issue that seem to be growing and is costing a lot of money to deal with. If you want to read more about this, there is some good general information at UCIPM

So, this season the new pest on the block was European Grapevine Moth. This pest started up in Napa county in 2008 and was actually identified in 2009 and programs were put in place to try to keep it contained and eradicate it from the area. This year the California Department of Food and Ag (CDFA) put traps out in all the counties to see if the pest have spread beyond Napa. Unfortunately, it has spread and, as of the writing of this blog, 10 California counties now have quarantine areas for this pest. This is a moth and the larvae get into the grape clusters and feed on the berries causing a lot of rot and crop loss. There was a trap near some of my grape and tree fruit growers that caught moths and triggered a quarantine area. One grower had all of their orchards and vineyards in the zone and one that had it’s packing shed in the zone. The grower that had the packing shed in the zone lost all of their export market to Mexico because even with all the precautions the state imposed, Mexico still would not accept fruit from the area. For growers in the zone, they were all strongly encouraged to spray more often to keep the pest from spreading. Luckily, this was a worm pest that had a life cycle similar to other worm pests we deal with and our normal program seemed to fit into the state’s needs. The only crop that needed extra sprays were the raisins since we usually do not spray multiple time for worms in this crop.

The biggest issue for me with these pest are the headaches they cause for the whole system. Extra money and time being spent to track, inspect, spray, etc. Some of these pest can be really damaging, especially if they transmit diseases into the plants that we then cannot control. Plants that are infected with viruses are usually done for, as we have no way to treat these.

So take the threat of Invasive Pests seriously. They are a big threat, not just to agriculture but to our rivers, streams and other wildlife as well. For more information, check out these links:

California Invasive Species info
CDFA Battle Against Invasive Species

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