By: Kristi Waterworth
Sometimes, it’s a wonder that anybody bothers growing anything, with all the diseases, problems and pests that plants seem to attract out of nowhere. Take leafroller insects — the adult moths that are responsible for the caterpillars are well-camouflaged, appearing in colors ranging from brown to gray, and they certainly don’t look like trouble. Shortly after these plain moths have visited the garden, you may notice the appearance of rolled or folded leaves containing hungry caterpillars.
Leafrollers are small caterpillars, reaching about an inch (2.5 cm.) in length, often with dark heads and bodies in colors ranging from green to brown. They feed inside nests made from leaves of their host plants, rolled together and tied with silk. Once inside their leaf nests, leafrollers chew holes through the tissue, sometimes adding more leaves to the nest to keep themselves protected from predators.
Leafroller damage is usually minor, but some years it may be quite severe. When there are lots of nests in a plant, defoliation may occur. High numbers of leafrollers may also feed on fruits, causing scarring and deformation. Plants affected by leafrollers include most woody landscape plants and fruit trees like pears, apples, peaches and even coconuts.
A few leafrollers are nothing to worry about; you can easily cut the few damaged leaves from your plant and toss the caterpillars into a bucket of soapy water. Carefully pick through infested plants and those nearby to ensure you’ve gotten all the caterpillars, and check back weekly. Leafrollers don’t hatch all at once, especially if more than one species is present.
When numbers are very high, you may need chemical help. Bacillus thuringiensis works as a stomach poison to feeding caterpillars, and is extremely effective if applied to these pests and their food source while they’re young. It can be difficult to get sprays inside the rolled up nests, but if you can’t simply cut the caterpillars out, this is the next best option if you wish to preserve the natural enemies of the leafrolling caterpillars in your landscape.
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Insecticidal oil sprays applied in dormancy for scales and other insects will help control leafroller eggs on fruit trees. The microbial insecticide Bacillus thuringiensis, which is sold as a variety of products, is effective against the larval stages of leafrollers.
Subsequently, question is, will Sevin dust kill leaf rollers? A third treatment option to consider is a carbaryl insecticide such as Sevin. Alternating insecticides also prevents insects from building up resistance to any one particular method. Although the Canna Leaf Roller (Calpodes ethlius) does occur in our area, the Lesser Canna Leaf Roller is the predominate pest.
Herein, why are my Canna leaves curling?
Canna plants attract aphids, which can cause the leaves to turn yellow, curl or become distorted. The honeydew that aphids excrete can also cause the leaves of the canna plant to grow black mold. Rinse canna leaves with running water to wash away the aphids and their honeydew.
What bug eats Canna leaves?
Chewing pests Among the more common pests on Canna are caterpillars and larvae. Canna leafrollers are larvae of Brazilian skippers and chew straight rows of holes in leaves. Many other infant insects may find Canna leaves delicious.
The caterpillars of most species in the Tortricid moth family roll up leaves with their strong silk and hide inside while they feed. The behavior benefits the insect by shielding it from predators, but is of no benefit to the host plant. In large numbers, leafrollers can completely defoliate a tree in one season. Adult moths lay their eggs on smooth bark surfaces in late fall. The eggs overwinter and hatch in early spring. Caterpillars feed and grow throughout the summer, then pupate and become adults. Different species of leafroller are pests to a variety of ornamental, fruit and nut trees. The Light Brown Apple Moth, a non-native leafroller, recently invaded California and threatens more than 1,000 different plant species in the state. With only one generation per year, and prey to parasitic wasps, lacewings and beetles, control of leafrollers on your fruit trees is within reach.
Spray the infested tree with an insecticide containing Bacillus thuringiensis. This bacterium kills the soft-bodied caterpillars, but is safe for plants and other organisms.
Look for egg masses in late fall or early spring on the tree bark and in the joints of branches.
Brush or scrape the eggs off the tree and dispose of them far from susceptible plants.
Distribute lacewing eggs over the foliage of the fruit tree in early spring. As they hatch, the lacewing larvae consume both insect eggs and small caterpillars.
Release tricogramma wasps at the first sign of adult moths. These minute, parasitic wasps lay their eggs in the eggs of other insects, reducing or eliminating the need for leafroller control next season.
Jean Godawa is a science educator and writer. She has been writing science-related articles for print and online publications for more than 15 years. Godawa holds a degree in biology and environmental science with a focus on entomology from the University of Toronto. She has conducted field research in the tropical rainforests of southeastern Asia and South America.
Larger canna leaf roller. Photo by Diana Rashash
We are supposed to be north of the typical population area of larger canna leafrollers, but we’ve seen enough evidence the past couple of years: the two varieties of leafrollers, larger and smaller, that “roll” among us.
Your initial symptoms may be leaves that remain tightly folded, or that expand but have a line of holes or linear spots. As the season continues, the leaves might develop ragged edges and obvious signs of webbing.
If you find leafrollers gnawing on your cannas, alternate spraying products with the active ingredients spinosad and Bacillus thuringiensis (Bt) every week, making sure to spray down into the rolled-up leaves where caterpillars hide. (Spinosad can be applied up to 6 times per season, per crop, so alternating with Bt gives you a longer treatment window.) Consider acephate if the caterpillars are larger than 1/2 inch in length. Also, cut and remove all foliage from the site at the end of the season to reduce overwintering pupa.
Remember: early treatment helps reduce the population but, unless everyone in the neighborhood is treating their cannas, you might have to treat them again later.
Want to learn more about the pesky buggers? Check out these links:
By Dither Ocampo | Submitted On April 22, 2009
Many of your garden plants are in danger when infested by leaf rollers. These insects will eat and deform the leaves, making them look crumpled. As a result, the affected plants become unhealthy and look unsightly. You must learn how to get rid of leaf rollers, otherwise they may spread on to your other plants. With the proper techniques and chemical solutions, treating your garden shouldn't be too hard.
Types of Leaf Rollers
There are two types of leaf rollers that can attack your garden - the canna leaf roller and the lesser leaf roller. The canna leaf roller, which is the larva of the Brazilian skipper butterfly, infests mainly canna plants. It burrows and rolls itself in a leaf, deforming it in the process. The leaf serves as shelter and food for the garden pest. The lesser leaf roller, on the other hand, is the larva of a Geshna Cannalis moth. It attacks just like their larger cousins, only it spins strands around the leaf, which cause even more damage and deformity.
Manual Treatment Procedures
Removing leaf rollers can cause further leaf damage or even the removal of badly infected leaves. The insects are tightly bound, so ripping the infected portions of the leaves is necessary, unless you plan to use insecticides. The infected parts should be burned to eliminate the eggs, if there are any.
* Cut Off Badly Infected Leaves - If your canna plant still has a number of healthy leaves, you might as well cut off the damaged ones. By doing so, you can save the healthy leaves from infestation, keeping the pests away from them. Your plants will eventually grow new sets of leaves, so you shouldn't worry. Burn the damaged leaves to ascertain that the pests and the eggs will perish. You can't risk letting them crawl back to your plants.
* Pick off the Insects Manually - Partially damaged leaves can be saved by picking off the pests. Cut the insects' shelters open and extract the caterpillars. Burn them or throw them away, so they can't do any further damage. If you find the leaf rollers too icky, just wear gloves when extracting them.
* The Ladybug Treatment - The ladybug's diet consists mainly of garden pests. What you can do is, release an array of ladybugs on your garden. They will zero in on the caterpillars, taking them out of the infected leaves.
The manual procedures are quick, considering you only need to pull leaves or pick caterpillars. However, if you plan to save the leaves, you will need to apply chemicals.
Chemical solutions are your best buds when treating a leaf roller infestation. Not only do they control leaf rollers, some of them also conceal the damage on the leaves. The harshly formulated ones, however, kill off also the insects beneficial for the plants' growth. Wear gloves and protective gear when applying chemical solutions, since they are poisonous and may irritate the skin.
* Bacillus Thuringiensis Insecticide - Insecticides containing bacillus thuringiensis are potent worm and pest killers. Naturally, you can use them to get rid of leaf rollers. The solutions, once applied, stop the pests from eating the leaves and later annihilate them. The insecticides' effects last for only a couple of days, so you should monitor the state of your plants occasionally. Apply the manual procedures first.
* Systematic Insecticide - Systematic insecticides are more potent than regular ones, given their potent formulations. The results come faster, but on the downside, it can damage the leaves of some garden plants. Spray carefully when applying to prevent it from reaching nearby plants, otherwise you might ruin them just as much as the leaf roller infection.
* Carbaryl Insecticide - The insecticide, liquid in form, can easily penetrate the insects' shelters, killing them in the process. Effective as the solution is, it can also eliminate insects that are helpful for your garden. Just use it when the other types of insecticide fail.
* Fertilizers - Fertilizers may not always kill leaf rollers, but they certainly raise the leaves' durability, helping them avoid leaf roller infestations. They also make the soil richer, which in turn, provides the plants proper nourishment. If your focus is on killing leaf rollers, you're better off with alcohol fertilizers, otherwise organic ones. Organic fertilizers are safer and sometimes the more effective choices.
A common problem for chemical solutions is the stiff pricing on the market. You should have a considerable amounts of cash if you are to treat a large plot of infected plants. Ideally, the manual methods must be applied first to minimize consumption.
Proper Methods for Proper Situations
By applying the methods for removing leaf rollers, you can restore and preserve your garden after serious infection. Maximize the advantages of each treatment, which in effect, lowers your effort and spending. Remember, a leaf roller-free garden is often picturesque.
If you want to learn the detailed guide on getting rid of leaf rollers, visit How to Get Rid of Stuff.
Download the resource for the complete factsheet.