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Podborer
Podborer [Helicoverpa armigera (Hb.) and Heliothis spp.] (Lepidoptera: Noctuidae) infest many host plants, especially lentil, in West Asia and the Indian subcontinent.
H. armigera is a large brown moth (20 mm. long). The fully grown larvae (up to 40 mm long) may have different coloration, but most are green (Fig. 66). All larvae have characteristic and distinct light and dark bands along the sides.
The adult moths are active at night and lay eggs on the undersides of leaflets. The fully grown larvae drop to the soil for pupation. There are several generations per year, depending upon temperatures.
Type of injury: The small larvae feed by scraping the surface of leaflets; older larvae feed on foliage and flowers, and bore into the green pods to eat the seeds (Fig. 67).
Control: In most cases infestations are not so severe that control measures are required and would be economical. However, since this insect directly affects the seeds and thus yield, insecticide application might be necessary sometimes. Sprays of methidathion (SupracideR 0.5 kg a.i./ha), deltamethrin (Decis 38 g a.i./ha), endosulfan (Thiodan 35, 6 ml/L and others at the time of flowering/early pod-setting can provide adequate control.
Lima-bean pod borer
This insect [Etiella zinckenella (Treit.)] (Lepidoptera: Pyralidae) is found in USA, Europe, North and East Africa, Southwest Asia, India and Pakistan. Among other leguminous crops, lentils also are attacked.
The adult moths are 10- 12 mm long with a wingspan of 22-28 mm. The forewings are browngrey with a white anterior margin. The hind wings are lighter (Fig. 68). The larvae become 10-12 mm long, are greenish with a brown line and a brown head capsule.
The adult moths only live for I week. Eggs are laid near the calyx of the flowers or on pods. The larval period lasts for 2-3 weeks. Mature larvae leave the pods and drop to the soil for pupation. There can be 3 to 5 generations per year. The winter is passed as diapausing larvae.
Type of injury: 'Me larvae feed on the soft green seeds in the pods. All seeds of an infested lentil pod are destroyed.
Control: In most cases infestations are not so severe that control measures are required and would be economical. However, since this insect directly affects the seeds and thus yield, insecticide application might be necessary sometimes. Sprays of methidathion (SupracideR 0.5 kg a.i./ha), deltamethrin (Decis 38 g a.i./ha), endosulfan (Thiodan 35, 6 ml/L) and others at the time of flowering/early pod-setting can provide adequate control.
Root aphid
Lentil infestation by the root aphid (Smynthurodes betae Westwood) (Homoptera: Aphididae) has been reported from Syria. In some years yellow patches can be found in lentil fields (Fig. 69). In the uprooted plants, white woolly aphids are present on the roots (Fig. 70).
It is a heteroecious species with a 2-year cycle. It forms yellowish to red galls on the primary host pistachio by rolling the leaf edge into a spindle near the leaf base. Secondary hosts consist of many dicotyledonous plants including Leguminosae of which only the roots are infested. The root aphid is not normally regarded as economically important.
Leafminers
Several species of leafminer (Liriomyza and Phytomyza spp.) (Diptera: Agromyzidae) can be occasionally found on lentil in West Asia, North Africa and South America.
The larvae feed inside the leaves, forming mines in which the larvae can be seen (Fig. 71). Heavy infestations lead to defoliation. The adult females lay the egg inside the leaf. The fully grown larvae leave the leaves and mostly drop to the soil for pupation.
No control measures are required.
Green stink bug
Green stink bug (Nezara viridula (L.)] (Hemiptera: Pentatomidae) is a highly polyphageous species with cosmopolitan distribution (Africa, Asia, Australia, Europe, USA).
The stink bug is 14-18 mm long, green and shield-shaped with a small head (Fig. 72).
The bugs suck the sap from leaves, stems and pods, which can cause malformations or drying up of the pods.
The stink bug is found on lentil, but does not require control measures.
Lygus bugs
Lygus spp. (Hemiptera: Miridae) are general feeders that attack several crops. In the western USA they have caused damage on lentil.
The adult Lygus bugs are about 6 mm long, flattened, oval and of various colors from pale green to yellowish brown (Fig. 73).
The bugs puncture the tissue and feed on the immature reproductive structure causing the "chalky spot syndrome" (physical deformations) of lentil seeds. The feeding also increases prevalence of shrivelled, unfilled pods and seed abortion.
No control measures have been reported on lentil.
Alfalfa weevil
The alfalfa weevil (Hypera postica Gyllenhal) (Coleoptera: Curculionidae) is widely distributed in West Asia and Europe and has been introduced into the USA. Alfalfa is the most important host plant and is severely damaged by the alfalfa weevil. Occasionally, lentils are attacked.
The adult beetles are 3-6 mm long, greyish brown/black with short greyish hairs, with a beak about half the length of the thorax (Fig. 74). Usually only the adults feed on lentil, eating out small holes from the leaflets, but no economic damage is caused.
Semilooper
Semilooper [Autographa gamma (L.)] (Lepidoptera: Noctuidae) is a polyphageous species feeding on a range of host plants. In Syria the semilooper larvae (reduced number of prolegs) have been reported to feed on lentil leaves. No economic damage has been reported.
Armyworm
This pest [Spodoptera exigua (Huebner)] (Lepidoptera: Noctuidae) is widely distributed throughout the tropics and subtropics and has been reported on lentil in eastern Mediterranean countries and India. It is a polyphageous species.
The moths have a greyish brown body and forewings: hind wings are semitransparent with a dark margin; the wingspan is 25-30 mm. The larvae are light green, often with stripes along the body.
Armyworm moths lay egg masses of pinkishwhite eggs at night. The larvae primarily feed at night and hide during the day. The fully grown larva (25-30 mm) buries into the soil for pupation. Depending upon the climate, several generations per year are completed. The larvae feed on the foliage and only severe infestations can defoliate the plants.
Armyworm rarely causes economic damage in lentil.
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