Mole Cricket

Latin name | Common name | Symptoms | Confirmation | Problems with similar symptoms | Why and where it occurs | Causal agent | Host range | Life cycle | Mechanism of damage | When damage is important | Economic importance | Management principles | Selected references | Contributors

Mole cricket adult (IRRI)

Diagnostic summary

Damage to plants	feeding on seeds fed-upon tillers in mature plants visible feeding damage on roots plants cut at the base loss of plant stand
Signs	presence of tan nymphs in tunnels on soil areas near the roots brown adults
Factors favoring insect/pest development	non-flooded upland fields presence of alternate hosts burrows or foraging-galleries in levees or field borders

Full fact sheet

Common name	Mole cricket
Latin names	Gryllotalpa orientalis Burmeister
Symptoms	Loss of plant stand Seedlings cut at the base Poor seedling growth Seedling death Missing plants Root damages Affected root system (IRRI)
Confirmation	The insect tunnels made by mole crickets appear as disturbed soil areas. The plants are cut at the base and the roots have visible feeding damage.
Problems with similar symptoms	Loss of plant stand and the missing plants are symptoms also caused by ants.
Why and where it occurs	Mole crickets occur in all rice environments. They are more common in non-flooded upland fields with moist soil. In flooded rice fields, mole crickets are usually seen swimming in the water. They are also found in permanent burrows or foraging-galleries in levees or field borders. The entrances to burrows in the soil are marked by heaps of soil. The nymphs feed on roots and damage the crops in patches.
Causal agent or factor	The adult mole cricket is brownish and very plump. It measures 25-40 mm long. It has short antennae and its folded wings do not cover the entire length of the abdomen. The enlarged front legs, which are modified for digging, have strong teeth-like structures. Neonate nymph has a white and bluish prothorax and legs. With age, it turns gray to black with white markings. The last nymphal stage is similar to the adult except for its short wing pads. Eggs are oblong to oval and gray with a shiny surface. They are 2.6 mm long. The eggs are deposited in a hole constructed by the adult female.
Host range	Besides rice, the insect pest feeds on Allium cepa L. (onion), Brassica oleraceae L. (cabbage), Camellia sinensis (L.) O. Ktze. (tea), Helianthus annuus L. (sunflower), Hordeum sp. (barley), Nicotiana tabacum L. (tobacco), Solanum tuberosum L. (white potato), and Triticum aestivum L. em. Thell. (wheat).
Life cycle
Mechanism of damage	The mole cricket tunnels into the soil using its enlarged fore legs. It feeds on seeds and resulting in loss of plant stand or poor crop stands.
When damage is important	Mole cricket is an important insect when flooded rice is drained or when water level varies exposing the soil. It feeds on rice during the seed to seedling stages of the crop.
Economic importance	Mole crickets are polyphagous. They feed on the underground parts of almost all-upland crops. They occasionally become sufficiently abundant to cause heavy damage to roots and basal parts of rice plants growing in raised nursery beds or upland conditions. In wetland rice, infestation occurs when there is no standing water.
Management principles	There are cultural control, biological control, and resistant varieties that can be used for mole crickets. For example, cultural control includes maintaining standing water, which can help remove the eggs on the soil. The eggs can also be eliminated using bund shaving and plastering of fresh wet soil. The rice field can be flooded for 3-4 days. Levelling the field provides better water control. Construction of a raised nursery should be avoided to reduce feeding damage on seedlings. During land preparation, the nymphs and adults can be collected. Modern varieties with long and dense fibrous can tolerate damage better. For natural biological control, a sphecid wasp, carabid beetle, nematodes, and a fungus are recorded as important natural enemies of the mole cricket. Mole crickets eat each other when they are together because of their cannibalistic behavior. There are poisoned baits made by mixing moistened rice bran and insecticide that can be placed along rice bunds or drier areas of the field, which can kill night-foraging mole crickets. Granular insecticides are effective unlike foliar insecticides.
Selected references	Hahn HE. 1958. Investigation on the habits and development of Gryllotalpa africana in Braudenberg. Berr. Entomol. 8:334-365. Pathak MD, Khan ZR. 1994. Insect pests of rice. Manila (Philippines): International Rice Research Institute. 89 p. Philippine Rice Research Institute (PhilRice). 1999. Field guide on harmful and useful organisms in Philippine ricefields. DA-PhilRice Maligaya, Muñoz, Nueva Ecija. 58 p. Reissig WH, Heinrichs EA, Litsinger JA, Moody K, Fiedler L, Mew TW, Barrion AT. 1986. Illustrated guide to integrated pest management in rice in tropical Asia. Manila (Philippines): International Rice Research Institute. 411 p. Shepard BM, Barrion AT, Litsinger JA. 1995. Rice-feeding insects of tropical Asia. Manila (Philippines): International Rice Research Institute. 228 p.
Contributors	JLA Catindig and KL Heong