Life cycle and symptoms of infestation:
The lesser date worm (Humira) is one of the early pests in the fruiting season.
It is considered one of the dangerous pests in Egypt, where the average infestation rate is 24% in May, as well as in some Arab countries such as Yemen, where the average infestation rate reached 74%, and in Iraq, Sudan, Saudi Arabia, Syria, Libya and Palestine.
The insect female lay 6-25 eggs on the flowers and fruits. The eggs hatch into larvae that attack the young fruits after fruit set through a fine tunnel made under the funnel and settle in the cavity of the soft kernel In the case of severe infestation, one larva can attack more than one fruit, and the larva usually weaves A silky thread surrounds the infested small fruit and connects it to the fruiting annulus. The growth of the infested fruits stops as a result of its feeding on the umbilical cord and separates from the anthers, but the silky thread made by the larva prevents It from falling in the case of small fruits. The color of the infested small fruits turns reddish-brown (for this reason it is called El Hamira) instead of green, and when the fruits are infested in the last stages of their growth, they fall to the ground due to the large size and weight of the fruits, or they do not fall, and this happens in July and August.
In order to differentiate between the falling of the date fruits resulting from the infestation with the lesser date worm (El Humira) and the natural fall of the fruits in the month of June, as the fallen date fruits due to the infestation with El Humira have white fluff and the excrement of the larvae at the place of their contact with the fruiting annulus, while these symptoms are not observed in the naturally fallen fruits in June .
The infestation begins at the end of March, immediately after the fruit set , and reaches its peak in May and the first half of June, and disappears at the beginning of September in the Rotab phase. The insect has three generations, the most dangerous of which is the first generation.
Protection and control methods:
- Mechanical control by pruning and removing the remnants of the previous date crop, including old bunches, old floral stalks, old dates falling in the axils of leaves and on the ground, and unknown dates (scattered), and the safe disposal of all these residues, including larvae and pupae, after harvesting the crop during October, November and December.
- Then the heart of the palm tree and around the place of exit of bunches and the bases of the leaves are dusting with agricultural sulfur.
- One of the recommended pesticides can be used to wash the heart of the palm and the bases of the leaf after date fruits collection and pruning.
- Attention to good agricultural practices service such as balanced fertilization, irrigation, good hoeing and weed disposal.
- Using behavioral control using light and sticky traps to monitor the emergence of adult insects since the beginning of the season in springer, as well as to eliminate them.
- Covering the shoots with paper bags in the form of an open funnel from the bottom to prevent the female moth from laying eggs on the fruits of dates reduces the infestation of El Humira insect.
• The use of biological control using the parasite Trichogramma for eggs and the parasite Bracon for larvae at the beginning of the appearance of eggs and larvae of the insect and throughout the season in the field.
• The use of biological control using insect pathogens such as Beauveria fungus and B.T. bacteria compounds and viruses.
• In the case of severe infestation and the failure of the previous methods to control the infestation, it is possible to spray after flowering and settling during the month of April with one of the following alternatives to insecticides such as Bt compounds (Protecito – Agrin – Dibel) at a rate of 100 cm / 100 liters of water or detergents at a rate of 1 liter / 100 liters of water or with the natural compound Tricer SC 24% (Spinosad) at a rate of 20 cm/100 liters of water. The treatment should be repeated two weeks after the first treatment.
Pictures showing the larva and the moth of the lesser date worm (El Humira)
Pictures showing the infestation symptoms of the lesser date worm (El Humia)
