Harm and Control Methods of the White-Spotted Flower Chafer on Sunflowers
Damage characteristics: The 1st-2nd instar larvae feed on the tubular flowers; after the 3rd instar they bore along the gaps between the sunflower seeds and feed on the seeds, eating part or all of the seed kernel, resulting in empty shells or bored seed heads. They bore many tunnels in the flower head and spin silk webs on the seeds of the head, binding together insect droppings and debris, forming a felt-like mass. The damaged flower heads mostly rot and become moldy, ...
Morphological characteristics: The adult body is 17-24 mm long and 9-12 mm wide. Oval, with a bronze or copper-green luster, and numerous irregular white felt-like spots scattered over the body surface. The front edge of the clypeus is folded and tilted upward, concave in the middle, with a border on each side, and sloping downward on the outer side; the antennae are dark brown; the compound eyes protrude; the pronotum has irregular white felt-like spots and is concave in the middle of the posterior margin; between the posterior angle of the pronotum and the anterior angle of the elytra there is a very conspicuous triangular piece, namely the posterior lateral plate of the mesothorax; the elytra are broad and nearly rectangular, covered with coarse punctures, and the white felt-like spots are mostly in transverse wavy shapes; the pygidium is short and broad, with 3 white felt-like spots on each side arranged in a triangle; the sides of abdominal ventrites 1-5 have white felt-like spots; the legs are relatively stout, with white felt-like spots at the knees; the posterior outer end angle of the hind coxa is sharp; the outer margin of the fore tibia has 3 teeth, and the tip of each tarsus has 2 curved claws.
Life habits: 1 generation per year. Adults begin to appear in early May, with the peak occurrence from June to July. The adults are active during the day, have a feigning-death habit, are attracted to the smell of wine and vinegar, are strong fliers, and often gather in groups to damage the flowers of seed vegetables and corn silks, laying eggs in the soil. The larvae mostly feed on decaying matter and move with their backs on the ground.
Control methods: (1) See the northeastern black chafer. (2) In the early occurrence period of the white-spotted flower chafer, hang narrow-mouthed bottles on sunflowers or corn and on nearby trees; either wine bottles or cleaned empty pesticide bottles can be used. Hang the bottles at a height of 1-1.5 m, and put 2-3 white-spotted flower chafers in each bottle. When the white-spotted flower chafers in the field fly to the bottles, they first crawl around near the bottle mouth and then fall into the bottle. Hanging 40-50 bottles per 667 sq m can trap and kill the white-spotted flower chafers, with excellent results.