Should You Spray or Dust?

If the chemical being applied is a contact poison, you must actually spray the bugs for it to work. A pressurized tank sprayer works best in most cases because you can spray under the leaves without losing pressure. One of the worst ways to apply dusts is to sprinkle them out of the container -- the holes are either too large or too small, and getting dust on the underside of leaves is almost impossible. One drawback to the traditionally popular dust gun is that it doesn't hold much dust and must be refilled often. The long barrel of the dusting tube helps prevent inhalation of the dust, and the angle of the nozzle allows for reaching under plants. Even better: the tube accepts both sprays and dusts.  REAL VIDEO Find out more about dust applicators.

When it comes to protecting your plants from bugs, the pesticides available often exist both as a spray and as a dust. So which do you choose? Since the active ingredients are the same in either form, that decision usually boils down to personal preference.

Before you buy anything, however, consider the economics of your choices. Say you have $10 to spend, here's what you can expect to buy for the money:  

Ten dollars' worth of liquid concentrate might make up to 32 gallons of spray, enough for several years! The downside is that concentrates require a lot of precise mixing and measuring.

A ready-to-mix formula is more convenient than a concentrate but will probably last through just one season.

Dusts are more expensive and will most likely be used up in little more than a month.

Even still, some people have a preference no matter what the price. Let's take a closer look.

Sprays

One drawback to sprays is that they don't adhere to glossy or waxy leaf surfaces very well. Consequently, more of the solution ends up dripping on the ground than sticking to leaves. To remedy the problem, look for a "spreader-sticker" wherever you buy lawn and garden chemicals. These products help bind the chemical solution to leaf surfaces without altering the chemical's effectiveness. Simply add a measured dose to the sprayer, mix well, and spray in the morning or evening when beneficial bugs (you don't want to kill those) are less likely to be around and winds are calmer.

If the spray is a poison that must be ingested, be sure to wet the leaves thoroughly, especially the undersides, where most bugs hide and feed.

Dusts

While virtually every lawn and garden chemical is available in spray form,fewer are available as dusts. In many cases it's because the chemical can't be formulated in dust form.

As with sprays, you should apply dusts in the early morning and evening hours. Several gadgets are available to apply chemical dusts to plants, including the dust gun and dust tube. Whatever you do, don't apply dusts with your hands. You won't get even coverage and you may actually poison yourself.

Take a look at one of the best dust applicators on the market.

Another question many gardeners ask is whether you should apply dust to wet or dry leaf surfaces? It's true that when you apply dust to wet leaves it sticks better , but it also leaves behind an unattractive residue. For that reason, Paul prefers to dust dry.

If you're still not sure whether you want to use a spray or a dust, look for a wetable powder. This "hybrid" product is sold as a dust but then mixed with water and sprayed on plants. Sulfur, for example, is a wetable powder that may be applied as a fungicide.