Pest Type: Rice Pest
Family: Arthropods – Arthropod
Class: Chaffinch – Branchiata
Row: Crustacea – Crustacea
Contract: Leaf-footed Crustacea – Phyllopoda
Ubiquitous crustacean damages rice in areas of its cultivation. Fossil animal, almost unchanged over 185 million years. Adult crustacean reaches 50-55 mm. The body is ovoid.
It is called a shield due to the fact that the cephalothorax is covered by an oval chitinous shield of a grayish-green color with a longitudinal keel in the middle. The back of the abdomen is thin and short, with two thin long appendages, protrudes from under the shield, the length of which exceeds the length of the body. Ruminant jaws are well developed, allow you to eat small animals, including a fish fry, underwater particles of plants. A pair of complex eyes and a simple point provide an overview of the upper side. On the underside of the shield, there are several dozens of pairs of limbs that perform the functions of movement, respiratory and auxiliary – to grab small animals and transfer them to the mouth.
Shield eggs are covered with dense shells, providing viability in case of drying out of the reservoir, freezing for 7-9 years. Larvae appear in rice fields, in puddles, ponds, in early May. They have three pairs of legs, bodies without segmentation. The development of larvae occurs within 2-3 weeks, and in June adult shields appear.
Damage to rice causes clouding of water. Shitnits gnaw rice sprouts and roots, eat lower leaves, plants often float to the surface of disturbed water. Annual generation. In the case of mass reproduction of the pest, the water layer is reduced to 3-4 cm and the low places where the shields are collected are treated with bleach with a consumption rate of 10-15 kg/ha. Examination of the fields is carried out in a critical period between the rice stairs and their appearance above the surface of the water.
Protective measures. Compliance with crop rotation with the inclusion of legumes. Optimally, early sowing times of rice with mandatory wrapping to a depth of 1.5-2.0 cm increase the stability of the stairs to damage. In the case of mass propagation of the shield during the germination of rice, complete drainage of water is mandatory for 2 to 3 days, and the pests die, not having time to lay eggs. In case of accumulation of crustaceans in low places, they are treated with bleach at a rate of 10-15 kg/ha. At present, the economic threshold for harmfulness is 7–10 ind./m2 of adult shield species.