Entomoscelis suturalis Weise, commonly known as the black-striped rapeseed leaf beetle, is a member of the order Coleoptera. It is also referred to as "Baum" or "black cockroach." This pest is primarily found in regions such as Hebei, Shanxi, Shaanxi, Jiangsu, and Gansu, where it infests cruciferous crops like rapeseed, cabbage, mustard, and radish. The beetle poses a significant threat to these plants, especially during their early growth stages. The larvae are the most destructive stage, feeding on leaves and creating irregular holes or short cuts. In severe cases, they can strip entire leaves or even damage the growing tip, leading to stunted growth, reduced seed production, or complete crop failure. Understanding the life cycle and behavior of this pest is crucial for effective control. Morphologically, adult males measure about 6mm in length, while females are slightly larger at 8mm. The head is black with a distinct crescent-shaped yellow spot. The compound eyes and antennae are black and elongated. The thorax is yellow with a prominent black "convex" spot in the center, along with two smaller black spots on each side. The elytra (wing covers) have a yellow-brown pattern with black intercostal lines. The head is deeply embedded in the thorax, and the antennae extend beyond the wing covers. The dorsal plate of the thorax is wide and arched at the back, covered in fine engravings. The small scutellum is semi-circular, and in females, the abdomen extends beyond the elytra. Eggs are oval, measuring approximately 1.8mm, and range in color from yellow to orange. The final larval stage reaches 10–13mm in length. The dorsal surface is dark brown, while the ventral side is lighter, often yellowish. The head is dark brown, with similar coloring at the front and end of the abdomen. Each body segment has three rows of dark brown tubercles, each with bristles. The beak is light yellow to orange, measuring around 6–7mm in length. In terms of life habits, this species completes one generation per year in provinces like Gansu, Shaanxi, and Shanxi. Adults lay eggs in the top soil near rapeseed roots, in cracks, soil clods, or under dead leaves. Hatching occurs when the rape starts to turn green. The larvae go through four instars and feed on oilseed rape, mustard, and cabbage from late March to early May. They are active between 8 and 17 hours a day, hiding under soil clods during the night, early morning, and rainy days. Larvae are known to feign death when disturbed. After mid-May, mature larvae burrow into the soil at depths of 2–6cm and emerge as adults after 10–15 days. By late May, they enter a dormant phase, and adults continue to infest crops after emerging. As summer ends, adults retreat into the soil at depths of 10–22cm. From late September to mid-October, they return to attack young seedlings. Between early October and November, females lay eggs in clusters within the root seams of rapeseed, typically laying around 200 eggs per female. By early November, males die off, leaving only the females to complete the cycle. For prevention, several methods are recommended. First, apply insecticide directly to the soil using 2.5% phoxim powder mixed with fine soil at a rate of 2kg per 667m² during sowing. This helps control overwintering adults and eggs. Second, after the rape is unearthed, if adults are detected in the field, spray 2.5% phoxim powder at 1–1.5kg per 667m² to eliminate adults and prevent egg-laying. Third, before planting, monitor egg density and hatching rates regularly. If more than one egg cluster is found per square meter and the hatching rate exceeds 80%, apply 2% Badan powder at 1.5–2kg per 667m² to target larvae at the early stage. Finally, during pod emergence, use 50% phoxim EC diluted 1500 times, 50% malathion EC diluted 1000 times, 2.5% kvitterin EC diluted 1500 times, 20% chloramphenicol diluted 1500–2000 times, or 0.6% flavescens nicotine alcohol solution diluted 1000–1500 times to manage infestations effectively.

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