Cycad small gray butterfly, also known as curved purple gray butterfly (scientific name: Chilades pandava) is an insect of the lepidoptera gray butterfly family. It mainly harms cycad plants. The larvae only endanger the new leaves that were extracted that year, and the hatching larvae sneak into the fist roll feather leaves to nibble on the young feather leaves, and the amount of food increases sharply with the age of the insects, resulting in the mutilation of the new feathers, and even only the petiole and leaf axis remain.
For harm:
Morphological characteristics:
Adult: 10–12 mm long, 20–35 mm wingspan, purplish-blue wing surface, black outer margin of the forewing, thin black and white edge of the outer edge of the hindwing, which is a narrow band of black inside. The reverse side of the wing is grayish brown, the margins are brown, both wings have black edges, the sub-outer margin of the forewing has 2 gray-white bands with white edges, and the posterior midternal spot column also has white edges, and the spots in chambers 2a and Cu2 are oblique, and the middle chamber end is rod-like. The hindwings have 2 bands with crescent white edges on the inside, cu2 ventricle ends are black with large orange maculas, posterior medial transverse column has a black spot in the middle and front and m2 to Cu2 chamber 3 spots are connected into a curved stripe, and the wing stem has 3 black spots, all with white circles. The caudal process is slender and the ends are white.
Eggs: 0.5-0.7 mm in diameter, grass green, flattened and round, slightly concave in the middle, rough surface with small notches and reticulations, scattered on the leaves, the egg body becomes darker when hatching. The larvae are 18-20 mm long, oblate oval, 3-5 mm wide, and the body color is changeable, with various colors such as green yellow, green, purple red, light yellow, brown yellow, etc., and the body is covered with short hairs, with multiple longitudinal stripes, including 1 bluish yellow and 3 red. The 7th abdominal segment has 1 dorsal gland that secretes honeydew.
Larvae: 4 instar, larvae of all ages are long and broad-headed. The body length and head width of the larvae of each age of the curved purple butterfly are as follows (in mm):
1-year body length: 1.5-1.8, average: (1.7); head width: 0.15-0.17, average: (0.16)
2-year-old body length: 3.1-4.2, average: (3.6); head width: 0.20-0.24, average: (0.22)
3-year-old body length: 6.4-8.4, average: (7.4); head width: 0.43-0.55, average: (0.49)
4-year-old body length: 10.6-12.5, average: (11.6); head width: 0.94-1.10, average: (1.02)
Pupa: oval, 810 mm long and 34 mm wide, brown on the back, covered with brownish-black short hairs, clearly demarcated between the thorax and abdomen, pale yellow ventral surface, pale green wing buds. The pre-feathered pupal color changes to a dark black.
Comparison of various insect states:
Life Habits:
Adults like to fly in open areas toward the sun, both male and female, active at a height of 12 meters above the ground, using nearby flowering plants as a source of honey. The eggs are scattered on the young buds of cycads, or on the back and stalks of new leaves. The initial spawning color is pale green, similar in color to the cycad buds and new leaves. The hatching larvae bite through the egg shell and crawl out, first feed the egg shell, and then drill moths from the outside of the new feather buds of the cycad to form a moth path, and eat all the way to the inside of the young leaf buds, the 2-3 year larvae often drill out of the moth path to the semi-unfolded young buds, and the 4-year-old mature larvae go down, hiding in the deciduous folds or the villi at the base of the plant leaves, stop feeding, and prepare to pupate. The larvae begin to feed from the base of the young leaves, and sometimes the mesophyll tissue can be eaten, leaving only the epidermis, which looks whitish from a distance, and the young leaves change color, wrinkle and dry after being damaged. If a large number of larvae are concentrated in the same leaf, they will eat only the epidermis. Larvae in the binge eating stage can see a large amount of insect droppings on the leaves and stems, and there is a stream of glue at the base of the leaf buds.
Adults of the curved purple gray butterfly can lay eggs the next day after feathering, and mating and laying eggs are mostly at 10-16 o'clock on sunny days. The eggs are scattered, mostly in the crevices of the fist-curled feather leaves or on unsveerized pinnae, and occasionally on the scales of the plant stem. The larvae hatch 1 h after starting to feed. Mature larvae usually pupate on the base of the feather leaf or on the gap between the scales, but also on the surface of the soil near the old feather leaf, plant pot or plant. The curved purple butterfly has a strong reproductive ability and vitality, and can still normalize pupae and feathering when it lacks nutrients, and the feathered adult insects can also reproduce normally.
The host is more than 30 species of plants in the cycad family Cycads. Generally, 6-7 generations occur every year, and March-October is its peak period. The first generation of larvae hatched in early to mid-March, the larvae only endangered the new leaves extracted that year, the hatching larvae sneaked into the fist roll feather leaf to nibble on the young feather leaf, commonly more than a dozen or even dozens, hundreds of larvae clustered on the new leaf as a pest, so that the feather leaf has just been extracted that has been eaten, and finally only the incomplete leaf shaft and petiole elongation, with the age of the insect to increase the amount of food increased sharply, and even only the petiole and leaf axis remained. Seriously affect the growth and ornamental value of cycads.
It is mainly distributed in India, Indonesia, Myanmar, Malaysia, Singapore, Sri Lanka, etc., and is endangered in Guangdong, Guangxi, Hong Kong and Taiwan in China. As the climate warms, the area of occurrence gradually shifts north.
After talking about the little gray butterfly, I will talk about cycads, there are many species under the cycad family, the most common is the iron tree. Originally a tropical plant, due to its beautiful shape, it was gradually trained into a green tree species. I like the sunny and humid environment. To say something crucial, the little gray butterfly is only to harm the new leaves, so what is the law of leaf extraction of the iron tree? In China, the time of leaf extraction of iron trees between different regions, and even the time of leaf extraction of iron trees in the same region are not the same. Generally speaking, the iron tree leaves are extracted once --- twice a year, and it is possible to pull leaves in different regions in the spring, autumn and summer. The same area is also unable to determine the iron tree unity at a time to draw leaves. This is the biggest problem with the control of small gray butterflies, which is not synchronized and can only be done together with the pest control of other green crops. Often miss the prevention and control time and cause harm, affecting the landscape effect.
But there was a favorable aspect, that is, he only wanted to harm the new leaf. And as soon as the iron tree opens the leaf extraction, the aging process will be completed quickly within two months, which means that as long as the leaf extraction begins, it will be no problem to protect for two months. Then our prevention and control strategy can start from how to protect this leaf extraction for two months.
Combined with the characteristics of the small gray butterflies in the front, the adults will fly, and the larvae will already be harmful, and the best strategy is not to let the small gray butterflies lay eggs. That is to say, find a way so that the little gray butterfly cannot lay eggs on the new leaves of the iron tree. In fact, many of my peers have already begun to do this, but they are all wrapped in gauze with wood chips soaked in potion. Realized, but the means are too low-end, one is that the drug has a taste, one is that the duration of the effect is too short, and there is no time, as long as it is an iron tree, there is no concept of the fertility period, resulting in poor actual performance.
In this regard, Henan Qilin reserves a lot of relevant technical and material data. Through industrialized standard production, the effectiveness of odorless low-toxic volatile agents is extended, and the validity period is more than 2 months, and it is not afraid of rain or sun, not afraid of wind. That is to say, a single medication can solve the problem of prevention and control of the iron tree butterfly. It is very simple to use, in the monthly routine inspection, if you find that the new shoots of the iron tree germinate and start to draw leaves, cut off the two corners of the product and put it in the new shoots of the iron tree. Wait until the leaves are finished and put away and throw them in the trash. The effect is one word "Absolutely!" ”
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Of course, if you don't like this way, you can use the traditional way. A bottle of 300 kg of water such as Qilin Guangzheng, Qi Fa and Huo Ji can be controlled by direct spraying at the larval stage. If the technique is good, it is best to be able to check the eggs directly at the egg stage.
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