I am/was battling them as well, here's some good info on them:
The All-Too-Common Aphid
Page Intro: Aphids are common everywhere and I mean everywhere. More growers report about aphids than any other pest. On this page you can get some background, learn how they become a problem, be introduced to exponential growth, learn that aphids are a serious pest, get some advice, find out what’s in store for the scout, then finally get some solutions.
Some Background
Aphids, members of the order Homoptera, are probably the most notorious pests in the world-what with well over 4000 species of aphids in this huge order, there is an aphid for everyone. Nearly everyone in horticulture and agriculture may have to, at some point in time, deal with aphids. They are often one of the first pests to appear — usually very early in the season. Some of the reason for this may have to due to their life-cycle but, perhaps, it is because they love tender new growth. Aphids are called plant lice by some people, though based on my experiences, this is not typical. Typical to my ears is nomenclature more along the lines of %#@&$? or @$#?&%. I have discovered most growers are not terribly fond of these opportunistic little creatures. [Intro]
How They Become a Problem
Trouble often starts in greenhouses when the operator cranks up the heat a little as the plant material he or she has sown begins to germinate and leaf out. Normally aphids don’t attack the cotyledons, but are keen on any new growth beyond that point. They usually stay on the newest growth and follow it upward as the plant develops — all the way through the budding and flowering stages. Aphids tend to be communal, blanketing new growth the way a beard will blanket a chin.
The infestation process begins as winged adult aphids come in from their winter hideaways (usually the craggy bark of nearby trees) during early spring weather warm enough to allow their flight and migration, and this can be very early in the season. Exception to this rule, of course, will include human introductions where aphids are brought into a structure hitchhiking on purchased plants. Remember: scout new plant material thoroughly before bringing it into your greenhouse. [Intro]
Exponential Growth
The winged adults light on plants ready to give birth, which, mostly in greenhouses is done viviparously — in other words, they bear wingless living young, skipping the egg-laying stage entirely. This gives aphids a unique time-saving advantage. To further compound the speed in which aphids can multiply, the nymphal or immature stages are entirely female and then reproduce further parthenogenetically, which means they have no need to mate. Adding insult to the grower’s injury, the nymphal stages are born with the next brood within them already, a condition called paedogenesis. To aphids the combination of these abilities spell exponential growth potential — to growers it means trouble if counteraction is not taken immediately. [Intro]
A Serious Pest
Aphids, if not defeated early in the game, before damaged parts can be auto-corrected and outgrown by the continued development of the plants, can cause considerable economical damage to an otherwise salable crop. An aphid feeds by inserting its proboscis, stylet or straw-like mouthpart into the phloem or inner cells of a plant. Upon insertion the aphid draws the plant’s juices or sap. This feeding activity will normally cause leaf and stem deformities. Moreover, it can aid the transmission of various plant diseases, both bacterial and viral. All of which can affect the plant’s appearance and value and may even, if left unchecked, kill the plant.
An additional problem which may also affect the aesthetics of the plant may include to presence of cast skins-a by-product of aphids molting from one nymphal stage to the next (which is occasionally confused by novices as stationary whiteflies for they’re white). Another aesthetics problem, if the population becomes large enough, is the formation of black-sooty mold which grows on the sugary, ant-attracting excrement of these pests. This excrement (a.k.a. poop) is known to attract sugar-feeding ants which may, in an effort to manage their food source, herd or physically move aphids and protect them from biocontrols, natural and introduced. This last condition, if the aphid population grows large enough to support ants, can make non-chemical control even more challenging.
As was written previously, winged aphids start the ball rolling. From that point on the aphids do not have wings and those forms will not be present. Therefore, if you detect some winged aphids your population is probably in its beginning stages. However, like everything else in the complicated world of pests, or so it seems, there are exceptions. In this case the exception is if your aphid population is in full swing, a brood of winged aphids will be developed. The reason for this is simple: the host plant is becoming overloaded and may not be able to support further aphid population growth. The colony wants to spread. In other words, if you detect plants loaded with aphids amongst which there are winged forms, the problem is quickly going to affect nearby plants. [Intro]
Some Advice
If it’s not apparent in this page, let me spell it out. Aphids can be a disastrous pest to have in your crop. The damage they can cause can be severe to the point of total crop loss. Your scouting must be thorough and regular — especially early in the season. Aphids aren’t usually difficult to spot, though they do go undetected by too many growers. Many growers, unfortunately, notice the ants or cast skins before they actually see the pests themselves. This is unnecessary, though, as the first aphids should be easily noted with proper scouting. [Intro]
For the Scout
Aphids, at least the winged forms, may be inadvertently captured on sticky traps, but physical plant inspections are much more valuable to the scout. Many aphids are green in color which can make detection more difficult, but several species are not well camouflaged and can be quite colorful. Moreover, detection is aided as aphids tend to congregate on the growing tips and flower buds so the scout will know where to look and not be stuck searching for tiny individuals. The color of these three to six millimeter pests can range from yellow to red, green and blue to gray, and even black to white and fuzzy-looking. Most species have two hornlike structures, called cornicles, on the posterior end of their abdomens flanking a small caudal tail (they have a total of three things on their butt). Their antennae are rather long and are swept back toward their rear along the sides of their body. In combination, these features can aid in their identification. [Intro]
Some Solutions
There are many biological pest control agents available to specifically address aphid pests. Some, like the Aphidius spp., can be used preventively — which is highly recommended, especially when considering the awesome destructive potential of these pests. Chemical controls can also be effective, but great care must be taken as aphids can easily develop resistance to many pesticides.
In my opinion, if scouting is done right and if biocontrols are used preventively, aphids can be a non-issue issue for growers. Control can be easily achieved, but only if aphids are understood and respected.
Looking for controls, try Aphidius spp., Aphidoletes aphidimyza, Chrysoperla spp., and Hippodamia convergens. Even the scale predatory beetle Harmonia axyridis can also help. There are also biorational sprays, soap and oil, and other goods that can do their part as well. [Intro]
The All-Too-Common Aphid
Page Intro: Aphids are common everywhere and I mean everywhere. More growers report about aphids than any other pest. On this page you can get some background, learn how they become a problem, be introduced to exponential growth, learn that aphids are a serious pest, get some advice, find out what’s in store for the scout, then finally get some solutions.
Some Background
Aphids, members of the order Homoptera, are probably the most notorious pests in the world-what with well over 4000 species of aphids in this huge order, there is an aphid for everyone. Nearly everyone in horticulture and agriculture may have to, at some point in time, deal with aphids. They are often one of the first pests to appear — usually very early in the season. Some of the reason for this may have to due to their life-cycle but, perhaps, it is because they love tender new growth. Aphids are called plant lice by some people, though based on my experiences, this is not typical. Typical to my ears is nomenclature more along the lines of %#@&$? or @$#?&%. I have discovered most growers are not terribly fond of these opportunistic little creatures. [Intro]
How They Become a Problem
Trouble often starts in greenhouses when the operator cranks up the heat a little as the plant material he or she has sown begins to germinate and leaf out. Normally aphids don’t attack the cotyledons, but are keen on any new growth beyond that point. They usually stay on the newest growth and follow it upward as the plant develops — all the way through the budding and flowering stages. Aphids tend to be communal, blanketing new growth the way a beard will blanket a chin.
The infestation process begins as winged adult aphids come in from their winter hideaways (usually the craggy bark of nearby trees) during early spring weather warm enough to allow their flight and migration, and this can be very early in the season. Exception to this rule, of course, will include human introductions where aphids are brought into a structure hitchhiking on purchased plants. Remember: scout new plant material thoroughly before bringing it into your greenhouse. [Intro]
Exponential Growth
The winged adults light on plants ready to give birth, which, mostly in greenhouses is done viviparously — in other words, they bear wingless living young, skipping the egg-laying stage entirely. This gives aphids a unique time-saving advantage. To further compound the speed in which aphids can multiply, the nymphal or immature stages are entirely female and then reproduce further parthenogenetically, which means they have no need to mate. Adding insult to the grower’s injury, the nymphal stages are born with the next brood within them already, a condition called paedogenesis. To aphids the combination of these abilities spell exponential growth potential — to growers it means trouble if counteraction is not taken immediately. [Intro]
A Serious Pest
Aphids, if not defeated early in the game, before damaged parts can be auto-corrected and outgrown by the continued development of the plants, can cause considerable economical damage to an otherwise salable crop. An aphid feeds by inserting its proboscis, stylet or straw-like mouthpart into the phloem or inner cells of a plant. Upon insertion the aphid draws the plant’s juices or sap. This feeding activity will normally cause leaf and stem deformities. Moreover, it can aid the transmission of various plant diseases, both bacterial and viral. All of which can affect the plant’s appearance and value and may even, if left unchecked, kill the plant.
An additional problem which may also affect the aesthetics of the plant may include to presence of cast skins-a by-product of aphids molting from one nymphal stage to the next (which is occasionally confused by novices as stationary whiteflies for they’re white). Another aesthetics problem, if the population becomes large enough, is the formation of black-sooty mold which grows on the sugary, ant-attracting excrement of these pests. This excrement (a.k.a. poop) is known to attract sugar-feeding ants which may, in an effort to manage their food source, herd or physically move aphids and protect them from biocontrols, natural and introduced. This last condition, if the aphid population grows large enough to support ants, can make non-chemical control even more challenging.
As was written previously, winged aphids start the ball rolling. From that point on the aphids do not have wings and those forms will not be present. Therefore, if you detect some winged aphids your population is probably in its beginning stages. However, like everything else in the complicated world of pests, or so it seems, there are exceptions. In this case the exception is if your aphid population is in full swing, a brood of winged aphids will be developed. The reason for this is simple: the host plant is becoming overloaded and may not be able to support further aphid population growth. The colony wants to spread. In other words, if you detect plants loaded with aphids amongst which there are winged forms, the problem is quickly going to affect nearby plants. [Intro]
Some Advice
If it’s not apparent in this page, let me spell it out. Aphids can be a disastrous pest to have in your crop. The damage they can cause can be severe to the point of total crop loss. Your scouting must be thorough and regular — especially early in the season. Aphids aren’t usually difficult to spot, though they do go undetected by too many growers. Many growers, unfortunately, notice the ants or cast skins before they actually see the pests themselves. This is unnecessary, though, as the first aphids should be easily noted with proper scouting. [Intro]
For the Scout
Aphids, at least the winged forms, may be inadvertently captured on sticky traps, but physical plant inspections are much more valuable to the scout. Many aphids are green in color which can make detection more difficult, but several species are not well camouflaged and can be quite colorful. Moreover, detection is aided as aphids tend to congregate on the growing tips and flower buds so the scout will know where to look and not be stuck searching for tiny individuals. The color of these three to six millimeter pests can range from yellow to red, green and blue to gray, and even black to white and fuzzy-looking. Most species have two hornlike structures, called cornicles, on the posterior end of their abdomens flanking a small caudal tail (they have a total of three things on their butt). Their antennae are rather long and are swept back toward their rear along the sides of their body. In combination, these features can aid in their identification. [Intro]
Some Solutions
There are many biological pest control agents available to specifically address aphid pests. Some, like the Aphidius spp., can be used preventively — which is highly recommended, especially when considering the awesome destructive potential of these pests. Chemical controls can also be effective, but great care must be taken as aphids can easily develop resistance to many pesticides.
In my opinion, if scouting is done right and if biocontrols are used preventively, aphids can be a non-issue issue for growers. Control can be easily achieved, but only if aphids are understood and respected.
Looking for controls, try Aphidius spp., Aphidoletes aphidimyza, Chrysoperla spp., and Hippodamia convergens. Even the scale predatory beetle Harmonia axyridis can also help. There are also biorational sprays, soap and oil, and other goods that can do their part as well. [Intro]
